Add support for carbon-cache service

Carbon-cache is the main service used for carbon, this patch starts to
add the first bits to allow a user to start using it.

Change-Id: Ib5cdd50ddb4be9d5249e785c92572292693f1978
Depends-On: https://review.openstack.org/588426
Depends-On: https://review.openstack.org/638056
Signed-off-by: Paul Belanger <pabelanger@redhat.com>

.zuul.yaml

@@ -2,8 +2,13 @@
     name: ansible-role-carbon-base
     pre-run: tests/playbooks/pre.yaml
     run: tests/playbooks/run.yaml
+    post-run: tests/collect-logs.yaml
     roles:
       - zuul: openstack/ansible-role-carbon
+      - zuul: openstack/ansible-role-whisper
+    vars:
+      # Default to python2 to make testing easier
+      carbon_pip_extra_args: --install-option='--install-scripts=/usr/local/bin' --install-option='--install-lib=/usr/local/lib/python2.7/dist-packages' --install-option='--install-data=/usr/local/share/carbon'
 
 # Testing for carbon_install_method: pip
 - job:
@@ -14,6 +19,8 @@
     name: ansible-role-carbon-fedora-latest
     parent: ansible-role-carbon
     nodeset: fedora-latest
+    vars:
+      carbon_pip_extra_args: --install-option='--install-scripts=/usr/local/bin' --install-option='--install-lib=/usr/lib/python2.7/site-packages' --install-option='--install-data=/usr/local/share/carbon'
 
 - job:
     name: ansible-role-carbon-ubuntu-bionic
@@ -31,11 +38,14 @@
     parent: ansible-role-carbon-base
     vars:
       carbon_install_method: git
+      whisper_install_method: git
 
 - job:
     name: ansible-role-carbon-src-fedora-latest
     parent: ansible-role-carbon-src
     nodeset: fedora-latest
+    vars:
+      carbon_pip_extra_args: --install-option='--install-scripts=/usr/local/bin' --install-option='--install-lib=/usr/lib/python2.7/site-packages' --install-option='--install-data=/usr/local/share/carbon'
 
 - job:
     name: ansible-role-carbon-src-ubuntu-bionic
@@ -56,7 +66,11 @@
         - ansible-role-carbon-src-fedora-latest
         - ansible-role-carbon-src-ubuntu-bionic
         - ansible-role-carbon-src-ubuntu-xenial
-        - tox-linters
+        - tox-linters:
+            required-projects:
+              - openstack/ansible-role-whisper
+            vars:
+              tox_install_siblings: false
     gate:
       jobs:
         - ansible-role-carbon-fedora-latest
@@ -65,4 +79,8 @@
         - ansible-role-carbon-src-fedora-latest
         - ansible-role-carbon-src-ubuntu-bionic
         - ansible-role-carbon-src-ubuntu-xenial
-        - tox-linters
+        - tox-linters:
+            required-projects:
+              - openstack/ansible-role-whisper
+            vars:
+              tox_install_siblings: false

defaults/main.yaml

@@ -12,7 +12,32 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 ---
+# tasks/main.yaml
+carbon_task_manager:
+  - pre
+  - install
+  - config
+  - service
+
+# tasks/pre.yaml
+carbon_user_name: carbon
+carbon_user_group: carbon
+carbon_user_home: /var/lib/carbon
+
 # tasks/config.yaml
+carbon_file_carbon_conf_dest: /etc/carbon/carbon.conf
+carbon_file_carbon_conf_group: "{{ carbon_user_group }}"
+carbon_file_carbon_conf_mode: 0644
+carbon_file_carbon_conf_owner: "{{ carbon_user_name }}"
+carbon_file_carbon_conf_src: etc/carbon/carbon.conf
+
+carbon_file_storage_schemas_conf_dest: /etc/carbon/storage-schemas.conf
+carbon_file_storage_schemas_conf_group: "{{ carbon_user_group }}"
+carbon_file_storage_schemas_conf_mode: 0644
+carbon_file_storage_schemas_conf_owner: "{{ carbon_user_name }}"
+carbon_file_storage_schemas_conf_src: etc/carbon/storage-schemas.conf
+
+# tasks/install.yaml
 carbon_git_dest: "{{ ansible_user_dir }}/src/github.com/graphite-project/carbon"
 carbon_git_uri: https://github.com/graphite-project/carbon
 carbon_git_version: master
@@ -21,8 +46,23 @@ carbon_git_version: master
 carbon_install_method: git
 
 carbon_pip_name: carbon
-# carbon_pip_executable:
 # carbon_pip_extra_args:
+# carbon_pip_executable:
 # carbon_pip_version:
 # carbon_pip_virtualenv_python:
 # carbon_pip_virtualenv:
+
+# tasks/service.yaml
+carbon_file_carbon_cache_service_manage: true
+carbon_file_carbon_cache_service_group: root
+carbon_file_carbon_cache_service_owner: root
+
+carbon_file_carbon_cache_service_config_manage: true
+carbon_file_carbon_cache_service_config_group: root
+carbon_file_carbon_cache_service_config_owner: root
+
+carbon_service_carbon_cache_daemon_reload: true
+carbon_service_carbon_cache_enabled: yes
+carbon_service_carbon_cache_manage: true
+carbon_service_carbon_cache_name: carbon-cache
+carbon_service_carbon_cache_state: started

tasks/config.yaml

@@ -0,0 +1,44 @@
+# Copyright 2015 Red Hat, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+---
+- name: Create required directories.
+  become: yes
+  file:
+    group: "{{ carbon_user_group }}"
+    owner: "{{ carbon_user_name }}"
+    path: "{{ item }}"
+    state: directory
+  with_items:
+    - /etc/carbon
+    - /var/log/carbon
+
+- name: Install carbon configuration.
+  become: yes
+  template:
+    dest: "{{ carbon_file_carbon_conf_dest }}"
+    group: "{{ carbon_file_carbon_conf_group }}"
+    mode: "{{ carbon_file_carbon_conf_mode }}"
+    owner: "{{ carbon_file_carbon_conf_owner }}"
+    src: "{{ carbon_file_carbon_conf_src }}"
+  register: carbon_file_carbon_conf
+
+- name: Install storage-schemas configuration.
+  become: yes
+  template:
+    dest: "{{ carbon_file_storage_schemas_conf_dest }}"
+    group: "{{ carbon_file_storage_schemas_conf_group }}"
+    mode: "{{ carbon_file_storage_schemas_conf_mode }}"
+    owner: "{{ carbon_file_storage_schemas_conf_owner }}"
+    src: "{{ carbon_file_storage_schemas_conf_src }}"
+  register: carbon_file_storage_schemas_conf

tasks/install.yaml

@@ -24,12 +24,4 @@
     state: installed
   when: carbon_install_method == 'git' or carbon_install_method == 'pip'
 
-- name: Define carbon_pip_executable if needed.
-  set_fact:
-    carbon_pip_executable: pip3
-  when:
-    - carbon_install_method == 'git' or carbon_install_method == 'pip'
-    - carbon_pip_virtualenv_python is not defined
-    - carbon_pip_executable is not defined
-
 - include: "install/{{ carbon_install_method }}.yaml"

tasks/main.yaml

@@ -15,4 +15,7 @@
 - name: Include OS-specific variables.
   include_vars: "{{ ansible_os_family }}.yaml"
 
-- include: install.yaml
+- include: "{{ carbon_task }}.yaml"
+  with_items: "{{ carbon_task_manager }}"
+  loop_control:
+    loop_var: carbon_task

tasks/pre.yaml

@@ -0,0 +1,26 @@
+# Copyright 2016 Red Hat, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+---
+- name: Create group account.
+  become: yes
+  group:
+    name: "{{ carbon_user_group }}"
+
+- name: Create user account.
+  become: yes
+  user:
+    createhome: yes
+    group: "{{ carbon_user_group }}"
+    home: "{{ carbon_user_home }}"
+    name: "{{ carbon_user_name }}"

tasks/service.yaml

@@ -0,0 +1,84 @@
+# Copyright 2015 Red Hat, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+---
+- name: Define carbon_file_carbon_cache_service_dest.
+  set_fact:
+    carbon_file_carbon_cache_service_dest: "{{ __carbon_file_carbon_cache_service_dest }}"
+  when: carbon_file_carbon_cache_service_dest is not defined
+
+- name: Define carbon_file_carbon_cache_service_mode.
+  set_fact:
+    carbon_file_carbon_cache_service_mode: "{{ __carbon_file_carbon_cache_service_mode }}"
+  when: carbon_file_carbon_cache_service_mode is not defined
+
+- name: Define carbon_file_carbon_cache_service_src.
+  set_fact:
+    carbon_file_carbon_cache_service_src: "{{ __carbon_file_carbon_cache_service_src }}"
+  when: carbon_file_carbon_cache_service_src is not defined
+
+- name: Define carbon_file_carbon_cache_service_config_dest.
+  set_fact:
+    carbon_file_carbon_cache_service_config_dest: "{{ __carbon_file_carbon_cache_service_config_dest  }}"
+  when: carbon_file_carbon_cache_service_config_dest is not defined
+
+- name: Define carbon_file_carbon_cache_service_config_mode.
+  set_fact:
+    carbon_file_carbon_cache_service_config_mode: "{{ __carbon_file_carbon_cache_service_config_mode  }}"
+  when: carbon_file_carbon_cache_service_config_mode is not defined
+
+- name: Define carbon_file_carbon_cache_service_config_src.
+  set_fact:
+    carbon_file_carbon_cache_service_config_src: "{{ __carbon_file_carbon_cache_service_config_src  }}"
+  when: carbon_file_carbon_cache_service_config_src is not defined
+
+- name: Install carbon-cache service script into place.
+  become: yes
+  template:
+    dest: "{{ carbon_file_carbon_cache_service_dest }}"
+    group: "{{ carbon_file_carbon_cache_service_group }}"
+    mode: "{{ carbon_file_carbon_cache_service_mode }}"
+    owner: "{{ carbon_file_carbon_cache_service_owner }}"
+    src: "{{ carbon_file_carbon_cache_service_src }}"
+  register: carbon_file_carbon_cache_service
+  when: carbon_file_carbon_cache_service_manage
+
+- name: Create carbon-cache service config directory.
+  become: yes
+  file:
+    group: "{{ carbon_file_carbon_cache_service_config_group }}"
+    owner: "{{ carbon_file_carbon_cache_service_config_owner }}"
+    path: "{{ carbon_file_carbon_cache_service_dest }}.d"
+    state: directory
+  when: carbon_file_carbon_cache_service_config_manage
+
+- name: Install carbon-cache service config into place.
+  become: yes
+  template:
+    dest: "{{ carbon_file_carbon_cache_service_config_dest  }}"
+    group: "{{ carbon_file_carbon_cache_service_config_group  }}"
+    mode: "{{ carbon_file_carbon_cache_service_config_mode  }}"
+    owner: "{{ carbon_file_carbon_cache_service_config_owner  }}"
+    src: "{{ carbon_file_carbon_cache_service_config_src  }}"
+  register: carbon_file_carbon_cache_service_config
+  when: carbon_file_carbon_cache_service_config_manage
+
+- name: Enable carbon-cache service.
+  become: yes
+  systemd:
+    daemon_reload: "{{ carbon_service_carbon_cache_daemon_reload }}"
+    enabled: "{{ carbon_service_carbon_cache_enabled }}"
+    name: "{{ carbon_service_carbon_cache_name }}"
+    state: "{{ carbon_service_carbon_cache_state }}"
+  register: carbon_service_carbon_cache
+  when: carbon_service_carbon_cache_manage

templates/etc/carbon/carbon.conf

@@ -0,0 +1,620 @@
+[cache]
+# Configure carbon directories.
+#
+# OS environment variables can be used to tell carbon where graphite is
+# installed, where to read configuration from and where to write data.
+#
+#   GRAPHITE_ROOT        - Root directory of the graphite installation.
+#                          Defaults to ../
+#   GRAPHITE_CONF_DIR    - Configuration directory (where this file lives).
+#                          Defaults to $GRAPHITE_ROOT/conf/
+#   GRAPHITE_STORAGE_DIR - Storage directory for whisper/rrd/log/pid files.
+#                          Defaults to $GRAPHITE_ROOT/storage/
+#
+# To change other directory paths, add settings to this file. The following
+# configuration variables are available with these default values:
+#
+#   STORAGE_DIR    = $GRAPHITE_STORAGE_DIR
+#   LOCAL_DATA_DIR = %(STORAGE_DIR)s/whisper/
+#   WHITELISTS_DIR = %(STORAGE_DIR)s/lists/
+#   CONF_DIR       = %(STORAGE_DIR)s/conf/
+#   LOG_DIR        = %(STORAGE_DIR)s/log/
+#   PID_DIR        = %(STORAGE_DIR)s/
+#
+# For FHS style directory structures, use:
+#
+#   STORAGE_DIR    = /var/lib/carbon/
+#   CONF_DIR       = /etc/carbon/
+#   LOG_DIR        = /var/log/carbon/
+#   PID_DIR        = /var/run/
+#
+#LOCAL_DATA_DIR = /opt/graphite/storage/whisper/
+
+STORAGE_DIR    = /var/lib/carbon/
+CONF_DIR       = /etc/carbon/
+LOG_DIR        = /var/log/carbon/
+PID_DIR        = /var/run/carbon/
+
+# Specify the database library used to store metric data on disk. Each database
+# may have configurable options to change the behaviour of how it writes to
+# persistent storage.
+#
+# whisper - Fixed-size database, similar in design and purpose to RRD. This is
+# the default storage backend for carbon and the most rigorously tested.
+#
+# ceres - Experimental alternative database that supports storing data in sparse
+# files of arbitrary fixed-size resolutions.
+DATABASE = whisper
+
+# Enable daily log rotation. If disabled, a new file will be opened whenever the log file path no
+# longer exists (i.e. it is removed or renamed)
+ENABLE_LOGROTATION = True
+
+# Specify the user to drop privileges to
+# If this is blank carbon-cache runs as the user that invokes it
+# This user must have write access to the local data directory
+USER =
+
+# Limit the size of the cache to avoid swapping or becoming CPU bound.
+# Sorts and serving cache queries gets more expensive as the cache grows.
+# Use the value "inf" (infinity) for an unlimited cache size.
+# value should be an integer number of metric datapoints.
+MAX_CACHE_SIZE = inf
+
+# Limits the number of whisper update_many() calls per second, which effectively
+# means the number of write requests sent to the disk. This is intended to
+# prevent over-utilizing the disk and thus starving the rest of the system.
+# When the rate of required updates exceeds this, then carbon's caching will
+# take effect and increase the overall throughput accordingly.
+MAX_UPDATES_PER_SECOND = 500
+
+# If defined, this changes the MAX_UPDATES_PER_SECOND in Carbon when a
+# stop/shutdown is initiated.  This helps when MAX_UPDATES_PER_SECOND is
+# relatively low and carbon has cached a lot of updates; it enables the carbon
+# daemon to shutdown more quickly.
+# MAX_UPDATES_PER_SECOND_ON_SHUTDOWN = 1000
+
+# Softly limits the number of whisper files that get created each minute.
+# Setting this value low (e.g. 50) is a good way to ensure that your carbon
+# system will not be adversely impacted when a bunch of new metrics are
+# sent to it. The trade off is that any metrics received in excess of this
+# value will be silently dropped, and the whisper file will not be created
+# until such point as a subsequent metric is received and fits within the
+# defined rate limit. Setting this value high (like "inf" for infinity) will
+# cause carbon to create the files quickly but at the risk of increased I/O.
+MAX_CREATES_PER_MINUTE = 50
+
+# Set the minimum timestamp resolution supported by this instance. This allows
+# internal optimisations by overwriting points with equal truncated timestamps
+# in order to limit the number of updates to the database. It defaults to one
+# second.
+MIN_TIMESTAMP_RESOLUTION = 1
+
+# Set the minimum lag in seconds for a point to be written to the database
+# in order to optimize batching. This means that each point will wait at least
+# the duration of this lag before being written. Setting this to 0 disable the feature.
+# This currently only works when using the timesorted write strategy.
+# MIN_TIMESTAMP_LAG = 0
+
+# Set the interface and port for the line (plain text) listener.  Setting the
+# interface to 0.0.0.0 listens on all interfaces.  Port can be set to 0 to
+# disable this listener if it is not required.
+LINE_RECEIVER_INTERFACE = 0.0.0.0
+LINE_RECEIVER_PORT = 2003
+
+# Set this to True to enable the UDP listener. By default this is off
+# because it is very common to run multiple carbon daemons and managing
+# another (rarely used) port for every carbon instance is not fun.
+ENABLE_UDP_LISTENER = False
+UDP_RECEIVER_INTERFACE = 0.0.0.0
+UDP_RECEIVER_PORT = 2003
+
+# Set the interface and port for the pickle listener.  Setting the interface to
+# 0.0.0.0 listens on all interfaces.  Port can be set to 0 to disable this
+# listener if it is not required.
+PICKLE_RECEIVER_INTERFACE = 0.0.0.0
+PICKLE_RECEIVER_PORT = 2004
+
+# Set the interface and port for the protobuf listener.  Setting the interface to
+# 0.0.0.0 listens on all interfaces.  Port can be set to 0 to disable this
+# listener if it is not required.
+# PROTOBUF_RECEIVER_INTERFACE = 0.0.0.0
+# PROTOBUF_RECEIVER_PORT = 2005
+
+# Limit the number of open connections the receiver can handle as any time.
+# Default is no limit. Setting up a limit for sites handling high volume
+# traffic may be recommended to avoid running out of TCP memory or having
+# thousands of TCP connections reduce the throughput of the service.
+#MAX_RECEIVER_CONNECTIONS = inf
+
+# Per security concerns outlined in Bug #817247 the pickle receiver
+# will use a more secure and slightly less efficient unpickler.
+# Set this to True to revert to the old-fashioned insecure unpickler.
+USE_INSECURE_UNPICKLER = False
+
+CACHE_QUERY_INTERFACE = 0.0.0.0
+CACHE_QUERY_PORT = 7002
+
+# Set this to False to drop datapoints received after the cache
+# reaches MAX_CACHE_SIZE. If this is True (the default) then sockets
+# over which metrics are received will temporarily stop accepting
+# data until the cache size falls below 95% MAX_CACHE_SIZE.
+USE_FLOW_CONTROL = True
+
+# If enabled this setting is used to timeout metric client connection if no
+# metrics have been sent in specified time in seconds
+#METRIC_CLIENT_IDLE_TIMEOUT = None
+
+# By default, carbon-cache will log every whisper update and cache hit.
+# This can be excessive and degrade performance if logging on the same
+# volume as the whisper data is stored.
+LOG_UPDATES = False
+LOG_CREATES = False
+LOG_CACHE_HITS = False
+LOG_CACHE_QUEUE_SORTS = False
+
+# The thread that writes metrics to disk can use one of the following strategies
+# determining the order in which metrics are removed from cache and flushed to
+# disk. The default option preserves the same behavior as has been historically
+# available in version 0.9.10.
+#
+# sorted - All metrics in the cache will be counted and an ordered list of
+# them will be sorted according to the number of datapoints in the cache at the
+# moment of the list's creation. Metrics will then be flushed from the cache to
+# disk in that order.
+#
+# timesorted - All metrics in the list will be looked at and sorted according
+# to the timestamp of there datapoints. The metric that were the least recently
+# written will be written first. This is an hybrid strategy between max and
+# sorted which is particularly adapted to sets of metrics with non-uniform
+# resolutions.
+#
+# max - The writer thread will always pop and flush the metric from cache
+# that has the most datapoints. This will give a strong flush preference to
+# frequently updated metrics and will also reduce random file-io. Infrequently
+# updated metrics may only ever be persisted to disk at daemon shutdown if
+# there are a large number of metrics which receive very frequent updates OR if
+# disk i/o is very slow.
+#
+# naive - Metrics will be flushed from the cache to disk in an unordered
+# fashion. This strategy may be desirable in situations where the storage for
+# whisper files is solid state, CPU resources are very limited or deference to
+# the OS's i/o scheduler is expected to compensate for the random write
+# pattern.
+#
+CACHE_WRITE_STRATEGY = sorted
+
+# On some systems it is desirable for whisper to write synchronously.
+# Set this option to True if you'd like to try this. Basically it will
+# shift the onus of buffering writes from the kernel into carbon's cache.
+WHISPER_AUTOFLUSH = False
+
+# By default new Whisper files are created pre-allocated with the data region
+# filled with zeros to prevent fragmentation and speed up contiguous reads and
+# writes (which are common). Enabling this option will cause Whisper to create
+# the file sparsely instead. Enabling this option may allow a large increase of
+# MAX_CREATES_PER_MINUTE but may have longer term performance implications
+# depending on the underlying storage configuration.
+# WHISPER_SPARSE_CREATE = False
+
+# Only beneficial on linux filesystems that support the fallocate system call.
+# It maintains the benefits of contiguous reads/writes, but with a potentially
+# much faster creation speed, by allowing the kernel to handle the block
+# allocation and zero-ing. Enabling this option may allow a large increase of
+# MAX_CREATES_PER_MINUTE. If enabled on an OS or filesystem that is unsupported
+# this option will gracefully fallback to standard POSIX file access methods.
+WHISPER_FALLOCATE_CREATE = True
+
+# Enabling this option will cause Whisper to lock each Whisper file it writes
+# to with an exclusive lock (LOCK_EX, see: man 2 flock). This is useful when
+# multiple carbon-cache daemons are writing to the same files.
+# WHISPER_LOCK_WRITES = False
+
+# On systems which has a large number of metrics, an amount of Whisper write(2)'s
+# pageback sometimes cause disk thrashing due to memory shortage, so that abnormal
+# disk reads occur. Enabling this option makes it possible to decrease useless
+# page cache memory by posix_fadvise(2) with POSIX_FADVISE_RANDOM option.
+# WHISPER_FADVISE_RANDOM = False
+
+# By default all nodes stored in Ceres are cached in memory to improve the
+# throughput of reads and writes to underlying slices. Turning this off will
+# greatly reduce memory consumption for databases with millions of metrics, at
+# the cost of a steep increase in disk i/o, approximately an extra two os.stat
+# calls for every read and write. Reasons to do this are if the underlying
+# storage can handle stat() with practically zero cost (SSD, NVMe, zRAM).
+# Valid values are:
+#       all - all nodes are cached
+#      none - node caching is disabled
+# CERES_NODE_CACHING_BEHAVIOR = all
+
+# Ceres nodes can have many slices and caching the right ones can improve
+# performance dramatically. Note that there are many trade-offs to tinkering
+# with this, and unless you are a ceres developer you *really* should not
+# mess with this. Valid values are:
+#    latest - only the most recent slice is cached
+#       all - all slices are cached
+#      none - slice caching is disabled
+# CERES_SLICE_CACHING_BEHAVIOR = latest
+
+# If a Ceres node accumulates too many slices, performance can suffer.
+# This can be caused by intermittently reported data. To mitigate
+# slice fragmentation there is a tolerance for how much space can be
+# wasted within a slice file to avoid creating a new one. That tolerance
+# level is determined by MAX_SLICE_GAP, which is the number of consecutive
+# null datapoints allowed in a slice file.
+# If you set this very low, you will waste less of the *tiny* bit disk space
+# that this feature wastes, and you will be prone to performance problems
+# caused by slice fragmentation, which can be pretty severe.
+# If you set this really high, you will waste a bit more disk space (each
+# null datapoint wastes 8 bytes, but keep in mind your filesystem's block
+# size). If you suffer slice fragmentation issues, you should increase this or
+# run the ceres-maintenance defrag plugin more often. However you should not
+# set it to be huge because then if a large but allowed gap occurs it has to
+# get filled in, which means instead of a simple 8-byte write to a new file we
+# could end up doing an (8 * MAX_SLICE_GAP)-byte write to the latest slice.
+# CERES_MAX_SLICE_GAP = 80
+
+# Enabling this option will cause Ceres to lock each Ceres file it writes to
+# to with an exclusive lock (LOCK_EX, see: man 2 flock). This is useful when
+# multiple carbon-cache daemons are writing to the same files.
+# CERES_LOCK_WRITES = False
+
+# Set this to True to enable whitelisting and blacklisting of metrics in
+# CONF_DIR/whitelist.conf and CONF_DIR/blacklist.conf. If the whitelist is
+# missing or empty, all metrics will pass through
+# USE_WHITELIST = False
+
+# By default, carbon itself will log statistics (such as a count,
+# metricsReceived) with the top level prefix of 'carbon' at an interval of 60
+# seconds. Set CARBON_METRIC_INTERVAL to 0 to disable instrumentation
+# CARBON_METRIC_PREFIX = carbon
+# CARBON_METRIC_INTERVAL = 60
+
+# Enable AMQP if you want to receve metrics using an amqp broker
+# ENABLE_AMQP = False
+
+# Verbose means a line will be logged for every metric received
+# useful for testing
+# AMQP_VERBOSE = False
+
+# AMQP_HOST = localhost
+# AMQP_PORT = 5672
+# AMQP_VHOST = /
+# AMQP_USER = guest
+# AMQP_PASSWORD = guest
+# AMQP_EXCHANGE = graphite
+# AMQP_METRIC_NAME_IN_BODY = False
+
+# The manhole interface allows you to SSH into the carbon daemon
+# and get a python interpreter. BE CAREFUL WITH THIS! If you do
+# something like time.sleep() in the interpreter, the whole process
+# will sleep! This is *extremely* helpful in debugging, assuming
+# you are familiar with the code. If you are not, please don't
+# mess with this, you are asking for trouble :)
+#
+# ENABLE_MANHOLE = False
+# MANHOLE_INTERFACE = 127.0.0.1
+# MANHOLE_PORT = 7222
+# MANHOLE_USER = admin
+# MANHOLE_PUBLIC_KEY = ssh-rsa AAAAB3NzaC1yc2EAAAABiwAaAIEAoxN0sv/e4eZCPpi3N3KYvyzRaBaMeS2RsOQ/cDuKv11dlNzVeiyc3RFmCv5Rjwn/lQ79y0zyHxw67qLyhQ/kDzINc4cY41ivuQXm2tPmgvexdrBv5nsfEpjs3gLZfJnyvlcVyWK/lId8WUvEWSWHTzsbtmXAF2raJMdgLTbQ8wE=
+
+# Patterns for all of the metrics this machine will store. Read more at
+# http://en.wikipedia.org/wiki/Advanced_Message_Queuing_Protocol#Bindings
+#
+# Example: store all sales, linux servers, and utilization metrics
+# BIND_PATTERNS = sales.#, servers.linux.#, #.utilization
+#
+# Example: store everything
+# BIND_PATTERNS = #
+
+# URL of graphite-web instance, this is used to add incoming series to the tag database
+# GRAPHITE_URL = http://127.0.0.1:80
+
+# Tag support, when enabled carbon will make HTTP calls to graphite-web to update the tag index
+# ENABLE_TAGS = True
+
+# Tag update interval, this specifies how frequently updates to existing series will trigger
+# an update to the tag index, the default setting is once every 100 updates
+# TAG_UPDATE_INTERVAL = 100
+
+# Tag hash filenames, this specifies whether tagged metric filenames should use the hash of the metric name
+# or a human-readable name, using hashed names avoids issues with path length when using a large number of tags
+# TAG_HASH_FILENAMES = True
+
+# Tag batch size, this specifies the maximum number of series to be sent to graphite-web in a single batch
+# TAG_BATCH_SIZE = 100
+
+# Tag queue size, this specifies the maximum number of series to be queued for sending to graphite-web
+# There are separate queues for new series and for updates to existing series
+# TAG_QUEUE_SIZE = 10000
+
+# Set to enable Sentry.io exception monitoring.
+# RAVEN_DSN='YOUR_DSN_HERE'.
+
+# To configure special settings for the carbon-cache instance 'b', uncomment this:
+#[cache:b]
+#LINE_RECEIVER_PORT = 2103
+#PICKLE_RECEIVER_PORT = 2104
+#CACHE_QUERY_PORT = 7102
+# and any other settings you want to customize, defaults are inherited
+# from the [cache] section.
+# You can then specify the --instance=b option to manage this instance
+#
+# In order to turn off logging of successful connections for the line
+# receiver, set this to False
+# LOG_LISTENER_CONN_SUCCESS = True
+
+[relay]
+LINE_RECEIVER_INTERFACE = 0.0.0.0
+LINE_RECEIVER_PORT = 2013
+PICKLE_RECEIVER_INTERFACE = 0.0.0.0
+PICKLE_RECEIVER_PORT = 2014
+
+# Carbon-relay has several options for metric routing controlled by RELAY_METHOD
+#
+# Use relay-rules.conf to route metrics to destinations based on pattern rules
+#RELAY_METHOD = rules
+#
+# Use consistent-hashing for even distribution of metrics between destinations
+#RELAY_METHOD = consistent-hashing
+#
+# Use consistent-hashing but take into account an aggregation-rules.conf shared
+# by downstream carbon-aggregator daemons. This will ensure that all metrics
+# that map to a given aggregation rule are sent to the same carbon-aggregator
+# instance.
+# Enable this for carbon-relays that send to a group of carbon-aggregators
+#RELAY_METHOD = aggregated-consistent-hashing
+#
+# You can also use fast-hashing and fast-aggregated-hashing which are in O(1)
+# and will always redirect the metrics to the same destination but do not try
+# to minimize rebalancing when the list of destinations is changing.
+RELAY_METHOD = rules
+
+# If you use consistent-hashing you can add redundancy by replicating every
+# datapoint to more than one machine.
+REPLICATION_FACTOR = 1
+
+# For REPLICATION_FACTOR >=2, set DIVERSE_REPLICAS to True to guarantee replicas
+# across distributed hosts. With this setting disabled, it's possible that replicas
+# may be sent to different caches on the same host. This has been the default
+# behavior since introduction of 'consistent-hashing' relay method.
+# Note that enabling this on an existing pre-0.9.14 cluster will require rebalancing
+# your metrics across the cluster nodes using a tool like Carbonate.
+#DIVERSE_REPLICAS = True
+
+# This is a list of carbon daemons we will send any relayed or
+# generated metrics to. The default provided would send to a single
+# carbon-cache instance on the default port. However if you
+# use multiple carbon-cache instances then it would look like this:
+#
+# DESTINATIONS = 127.0.0.1:2004:a, 127.0.0.1:2104:b
+#
+# The general form is IP:PORT:INSTANCE where the :INSTANCE part is
+# optional and refers to the "None" instance if omitted.
+#
+# Note that if the destinations are all carbon-caches then this should
+# exactly match the webapp's CARBONLINK_HOSTS setting in terms of
+# instances listed (order matters!).
+#
+# If using RELAY_METHOD = rules, all destinations used in relay-rules.conf
+# must be defined in this list
+DESTINATIONS = 127.0.0.1:2004
+
+# This define the protocol to use to contact the destination. It can be
+# set to one of "line", "pickle", "udp" and "protobuf". This list can be
+# extended with CarbonClientFactory plugins and defaults to "pickle".
+# DESTINATION_PROTOCOL = pickle
+
+# When using consistent hashing it sometime makes sense to make
+# the ring dynamic when you don't want to loose points when a
+# single destination is down. Replication is an answer to that
+# but it can be quite expensive.
+# DYNAMIC_ROUTER = False
+
+# Controls the number of connection attempts before marking a
+# destination as down. We usually do one connection attempt per
+# second.
+# DYNAMIC_ROUTER_MAX_RETRIES = 5
+
+# This is the maximum number of datapoints that can be queued up
+# for a single destination. Once this limit is hit, we will
+# stop accepting new data if USE_FLOW_CONTROL is True, otherwise
+# we will drop any subsequently received datapoints.
+MAX_QUEUE_SIZE = 10000
+
+# This defines the maximum "message size" between carbon daemons.  If
+# your queue is large, setting this to a lower number will cause the
+# relay to forward smaller discrete chunks of stats, which may prevent
+# overloading on the receiving side after a disconnect.
+MAX_DATAPOINTS_PER_MESSAGE = 500
+
+# Limit the number of open connections the receiver can handle as any time.
+# Default is no limit. Setting up a limit for sites handling high volume
+# traffic may be recommended to avoid running out of TCP memory or having
+# thousands of TCP connections reduce the throughput of the service.
+#MAX_RECEIVER_CONNECTIONS = inf
+
+# Specify the user to drop privileges to
+# If this is blank carbon-relay runs as the user that invokes it
+# USER =
+
+# This is the percentage that the queue must be empty before it will accept
+# more messages.  For a larger site, if the queue is very large it makes sense
+# to tune this to allow for incoming stats.  So if you have an average
+# flow of 100k stats/minute, and a MAX_QUEUE_SIZE of 3,000,000, it makes sense
+# to allow stats to start flowing when you've cleared the queue to 95% since
+# you should have space to accommodate the next minute's worth of stats
+# even before the relay incrementally clears more of the queue
+QUEUE_LOW_WATERMARK_PCT = 0.8
+
+# To allow for batch efficiency from the pickle protocol and to benefit from
+# other batching advantages, all writes are deferred by putting them into a queue,
+# and then the queue is flushed and sent a small fraction of a second later.
+TIME_TO_DEFER_SENDING = 0.0001
+
+# Set this to False to drop datapoints when any send queue (sending datapoints
+# to a downstream carbon daemon) hits MAX_QUEUE_SIZE. If this is True (the
+# default) then sockets over which metrics are received will temporarily stop accepting
+# data until the send queues fall below QUEUE_LOW_WATERMARK_PCT * MAX_QUEUE_SIZE.
+USE_FLOW_CONTROL = True
+
+# If enabled this setting is used to timeout metric client connection if no
+# metrics have been sent in specified time in seconds
+#METRIC_CLIENT_IDLE_TIMEOUT = None
+
+# Set this to True to enable whitelisting and blacklisting of metrics in
+# CONF_DIR/whitelist.conf and CONF_DIR/blacklist.conf. If the whitelist is
+# missing or empty, all metrics will pass through
+# USE_WHITELIST = False
+
+# By default, carbon itself will log statistics (such as a count,
+# metricsReceived) with the top level prefix of 'carbon' at an interval of 60
+# seconds. Set CARBON_METRIC_INTERVAL to 0 to disable instrumentation
+# CARBON_METRIC_PREFIX = carbon
+# CARBON_METRIC_INTERVAL = 60
+#
+# In order to turn off logging of successful connections for the line
+# receiver, set this to False
+# LOG_LISTENER_CONN_SUCCESS = True
+
+# If you're connecting from the relay to a destination that's over the
+# internet or similarly iffy connection, a backlog can develop because
+# of internet weather conditions, e.g. acks getting lost or similar issues.
+# To deal with that, you can enable USE_RATIO_RESET which will let you
+# re-set the connection to an individual destination.  Defaults to being off.
+USE_RATIO_RESET=False
+
+# When there is a small number of stats flowing, it's not desirable to
+# perform any actions based on percentages - it's just too "twitchy".
+MIN_RESET_STAT_FLOW=1000
+
+# When the ratio of stats being sent in a reporting interval is far
+# enough from 1.0, we will disconnect the socket and reconnecto to
+# clear out queued stats.  The default ratio of 0.9 indicates that 10%
+# of stats aren't being delivered within one CARBON_METRIC_INTERVAL
+# (default of 60 seconds), which can lead to a queue backup.  Under
+# some circumstances re-setting the connection can fix this, so
+# set this according to your tolerance, and look in the logs for
+# "resetConnectionForQualityReasons" to observe whether this is kicking
+# in when your sent queue is building up.
+MIN_RESET_RATIO=0.9
+
+# The minimum time between resets.  When a connection is re-set, we
+# need to wait before another reset is performed.
+# (2*CARBON_METRIC_INTERVAL) + 1 second is the minimum time needed
+# before stats for the new connection will be available.  Setting this
+# below (2*CARBON_METRIC_INTERVAL) + 1 second will result in a lot of
+# reset connections for no good reason.
+MIN_RESET_INTERVAL=121
+
+# Enable TCP Keep Alive (http://tldp.org/HOWTO/TCP-Keepalive-HOWTO/overview.html).
+# Default settings will send a probe every 30s. Default is False.
+# TCP_KEEPALIVE=True
+
+[aggregator]
+LINE_RECEIVER_INTERFACE = 0.0.0.0
+LINE_RECEIVER_PORT = 2023
+
+PICKLE_RECEIVER_INTERFACE = 0.0.0.0
+PICKLE_RECEIVER_PORT = 2024
+
+# If set true, metric received will be forwarded to DESTINATIONS in addition to
+# the output of the aggregation rules. If set false the carbon-aggregator will
+# only ever send the output of aggregation.
+FORWARD_ALL = True
+
+# Filenames of the configuration files to use for this instance of aggregator.
+# Filenames are relative to CONF_DIR.
+#
+# AGGREGATION_RULES = aggregation-rules.conf
+# REWRITE_RULES = rewrite-rules.conf
+
+# This is a list of carbon daemons we will send any relayed or
+# generated metrics to. The default provided would send to a single
+# carbon-cache instance on the default port. However if you
+# use multiple carbon-cache instances then it would look like this:
+#
+# DESTINATIONS = 127.0.0.1:2004:a, 127.0.0.1:2104:b
+#
+# The format is comma-delimited IP:PORT:INSTANCE where the :INSTANCE part is
+# optional and refers to the "None" instance if omitted.
+#
+# Note that if the destinations are all carbon-caches then this should
+# exactly match the webapp's CARBONLINK_HOSTS setting in terms of
+# instances listed (order matters!).
+DESTINATIONS = 127.0.0.1:2004
+
+# If you want to add redundancy to your data by replicating every
+# datapoint to more than one machine, increase this.
+REPLICATION_FACTOR = 1
+
+# This is the maximum number of datapoints that can be queued up
+# for a single destination. Once this limit is hit, we will
+# stop accepting new data if USE_FLOW_CONTROL is True, otherwise
+# we will drop any subsequently received datapoints.
+MAX_QUEUE_SIZE = 10000
+
+# Set this to False to drop datapoints when any send queue (sending datapoints
+# to a downstream carbon daemon) hits MAX_QUEUE_SIZE. If this is True (the
+# default) then sockets over which metrics are received will temporarily stop accepting
+# data until the send queues fall below 80% MAX_QUEUE_SIZE.
+USE_FLOW_CONTROL = True
+
+# If enabled this setting is used to timeout metric client connection if no
+# metrics have been sent in specified time in seconds
+#METRIC_CLIENT_IDLE_TIMEOUT = None
+
+# This defines the maximum "message size" between carbon daemons.
+# You shouldn't need to tune this unless you really know what you're doing.
+MAX_DATAPOINTS_PER_MESSAGE = 500
+
+# This defines how many datapoints the aggregator remembers for
+# each metric. Aggregation only happens for datapoints that fall in
+# the past MAX_AGGREGATION_INTERVALS * intervalSize seconds.
+MAX_AGGREGATION_INTERVALS = 5
+
+# Limit the number of open connections the receiver can handle as any time.
+# Default is no limit. Setting up a limit for sites handling high volume
+# traffic may be recommended to avoid running out of TCP memory or having
+# thousands of TCP connections reduce the throughput of the service.
+#MAX_RECEIVER_CONNECTIONS = inf
+
+# By default (WRITE_BACK_FREQUENCY = 0), carbon-aggregator will write back
+# aggregated data points once every rule.frequency seconds, on a per-rule basis.
+# Set this (WRITE_BACK_FREQUENCY = N) to write back all aggregated data points
+# every N seconds, independent of rule frequency. This is useful, for example,
+# to be able to query partially aggregated metrics from carbon-cache without
+# having to first wait rule.frequency seconds.
+# WRITE_BACK_FREQUENCY = 0
+
+# Set this to True to enable whitelisting and blacklisting of metrics in
+# CONF_DIR/whitelist.conf and CONF_DIR/blacklist.conf. If the whitelist is
+# missing or empty, all metrics will pass through
+# USE_WHITELIST = False
+
+# By default, carbon itself will log statistics (such as a count,
+# metricsReceived) with the top level prefix of 'carbon' at an interval of 60
+# seconds. Set CARBON_METRIC_INTERVAL to 0 to disable instrumentation
+# CARBON_METRIC_PREFIX = carbon
+# CARBON_METRIC_INTERVAL = 60
+
+# In order to turn off logging of successful connections for the line
+# receiver, set this to False
+# LOG_LISTENER_CONN_SUCCESS = True
+
+# In order to turn off logging of metrics with no corresponding
+# aggregation rules receiver, set this to False
+# LOG_AGGREGATOR_MISSES = False
+
+# Specify the user to drop privileges to
+# If this is blank carbon-aggregator runs as the user that invokes it
+# USER =
+
+# Part of the code, and particularly aggregator rules, need
+# to cache metric names. To avoid leaking too much memory you
+# can tweak the size of this cache. The default allow for 1M
+# different metrics per rule (~200MiB).
+# CACHE_METRIC_NAMES_MAX=1000000
+
+# You can optionally set a ttl to this cache.
+# CACHE_METRIC_NAMES_TTL=600

templates/etc/carbon/storage-schemas.conf

@@ -0,0 +1,7 @@
+[carbon]
+pattern = ^carbon\.
+retentions = 60:90d
+
+[default_1min_for_1day]
+pattern = .*
+retentions = 60s:1d

templates/etc/systemd/system/carbon-cache.service

@@ -0,0 +1,14 @@
+[Unit]
+Description=Graphite Carbon Cache
+After=syslog.target network.target
+
+[Service]
+Type=forking
+ExecStart={{ carbon_pip_virtualenv | default('/usr/local') }}/bin/carbon-cache.py --config=/etc/carbon/carbon.conf start
+Group=carbon
+PIDFile=/var/run/carbon/carbon-cache-a.pid
+RuntimeDirectory=carbon
+User=carbon
+
+[Install]
+WantedBy=multi-user.target

templates/etc/systemd/system/carbon-cache.service.d/override.conf

@@ -0,0 +1,3 @@
+# This file is generated by Ansible
+#  DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
+#

tests/collect-logs.yaml

@@ -0,0 +1,32 @@
+- hosts: all
+  tasks:
+    - name: Ensure journald logs directory exists
+      file:
+        path: "~/logs/var/log/journal"
+        state: directory
+
+    - name: Collect journald logs
+      shell: "sudo journalctl -u {{ item }}.service | tee ~/logs/var/log/journal/{{ item }}.service.log"
+      args:
+        creates: "~/logs/var/log/journal/{{ item }}.service.log"
+      with_items:
+        - carbon-cache
+
+    - name: Collect journalctl log files
+      synchronize:
+        dest: "{{ zuul.executor.log_root }}"
+        mode: pull
+        src: ~/logs
+        verify_host: true
+
+    - name: Collect statsd log files
+      synchronize:
+        dest: "{{ zuul.executor.log_root }}/logs"
+        mode: pull
+        rsync_opts:
+          - "--relative"
+        src: "{{ item }}"
+        verify_host: true
+      with_items:
+        - /etc/carbon
+        - /var/log/carbon

tests/playbooks/run.yaml

@@ -17,6 +17,7 @@
     rolename: ansible-role-carbon
 
   roles:
+    - ansible-role-whisper
     - "{{ rolename }}"
 
   post_tasks:
@@ -32,3 +33,36 @@
           - carbon_git_dest_stat.stat.exists
           - carbon_git_dest_stat.stat.isdir
       when: carbon_install_method == 'git'
+
+    - name: Register /etc/systemd/system/carbon-cache.service
+      stat:
+        path: /etc/systemd/system/carbon-cache.service
+      register: _carbon_cache_service_systemd_stat
+
+    - name: Assert _carbon_cache_service_systemd_stat tests.
+      assert:
+        that:
+          - _carbon_cache_service_systemd_stat.stat.exists
+          - _carbon_cache_service_systemd_stat.stat.isreg
+          - _carbon_cache_service_systemd_stat.stat.pw_name == 'root'
+          - _carbon_cache_service_systemd_stat.stat.gr_name == 'root'
+          - _carbon_cache_service_systemd_stat.stat.mode == '0644'
+
+    - name: Register /etc/systemd/system/carbon.cache.service.d/override.conf
+      stat:
+        path: /etc/systemd/system/carbon-cache.service.d/override.conf
+      register: _carbon_cache_service_config_stat
+
+    - name: Assert _carbon_cache_service_config_stat tests.
+      assert:
+        that:
+          - _carbon_cache_service_config_stat.stat.exists
+          - _carbon_cache_service_config_stat.stat.isreg
+          - _carbon_cache_service_config_stat.stat.pw_name == 'root'
+          - _carbon_cache_service_config_stat.stat.gr_name == 'root'
+          - _carbon_cache_service_config_stat.stat.mode == '0644'
+
+    - name: Ensure carbon-cache is running.
+      become: yes
+      shell: /usr/sbin/service carbon-cache status
+      tags: skip_ansible_lint

tox.ini

@@ -30,7 +30,7 @@ commands =
   flake8
   # Ansible Lint Check
   bash -c "find . -not -path '*/\.*' -type f -regex '.*.y[a]?ml' -print0 | \
-    xargs -t -n1 -0 ansible-lint"
+    xargs -t -n1 -0 ansible-lint -x306"
   # Ansible Syntax Check
   bash -c "find tests -type f -regex '.*.y[a]?ml' -print | xargs -t -n1 \
     ansible-playbook --syntax-check -i tests/inventory \

vars/Debian.yaml

@@ -13,3 +13,11 @@
 # under the License.
 ---
 __carbon_build_depends: []
+
+__carbon_file_carbon_cache_service_dest: /etc/systemd/system/carbon-cache.service
+__carbon_file_carbon_cache_service_mode: 0644
+__carbon_file_carbon_cache_service_src: etc/systemd/system/carbon-cache.service
+
+__carbon_file_carbon_cache_service_config_dest: /etc/systemd/system/carbon-cache.service.d/override.conf
+__carbon_file_carbon_cache_service_config_mode: 0644
+__carbon_file_carbon_cache_service_config_src: etc/systemd/system/carbon-cache.service.d/override.conf

vars/RedHat.yaml

@@ -13,3 +13,11 @@
 # under the License.
 ---
 __carbon_build_depends: []
+
+__carbon_file_carbon_cache_service_dest: /etc/systemd/system/carbon-cache.service
+__carbon_file_carbon_cache_service_mode: 0644
+__carbon_file_carbon_cache_service_src: etc/systemd/system/carbon-cache.service
+
+__carbon_file_carbon_cache_service_config_dest: /etc/systemd/system/carbon-cache.service.d/override.conf
+__carbon_file_carbon_cache_service_config_mode: 0644
+__carbon_file_carbon_cache_service_config_src: etc/systemd/system/carbon-cache.service.d/override.conf