openstack-ansible-lxc_conta.../tasks/lxc_container_create_cow.yml
Kevin Carter 25478e9b4e
Enable quota system and set qgroups
This change implements the machinectl quota system and qgroups when
they're enabled and available. This change is being implemented to
resolve an issue where machinectl based containers using a loopback file
system spam DMESG with the following:

* BTRFS error (device loop0): could not find root $INT

While various upstream sources say this error is benign[0], it raises
an inconsistency flag within the host system and is speculatively the
cause of our inconsistent read-only/Full-FS issues we've seen in the
integrated gate. Once the qgroups are properly setup the system will
remove the inconsistency flag and the message spam will stop.

* BTRFS info (device loop0): qgroup scan completed (inconsistency flag cleared)

To resolve this issue the quota system is being enabled by default
within the "lxc_host" role. This change essentially acknowledges
the built-in quota system and when enabled provides for the ability
to set / define specific quota (qgroup) options as necessary. While
many deployers may never use these options or this tooling, the role
will now properly set everything up should it ever be needed.

[0] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1651435
Closes-Bug: #1753790
Depends-On: I34a41ac8a9fe4419254284c83f4600efee274c04
Change-Id: Ica79472568799098ebf83c6cefc585f117975f37
Signed-off-by: Kevin Carter <kevin.carter@rackspace.com>
2018-05-14 22:33:44 -05:00

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2.4 KiB
YAML

---
# Copyright 2017, Rackspace US, 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.
# Due to https://github.com/ansible/ansible-modules-extras/issues/2577 the
# next two tasks do not use the lxc_container module.
# TODO(odyssey4me): Revisit this once a fix has merged
- name: Check if container exists
command: "lxc-info -n {{ inventory_hostname }}"
failed_when: false
delegate_to: "{{ physical_host }}"
register: lxc_container_info
# Due to https://bugs.launchpad.net/ubuntu/+source/lxc/+bug/1591510
# the '-B' option is used, instead of the more understandable
# '--backingstore'.
# TODO(odyssey4me): Revisit this once a fix has merged
- name: Create container (cow)
command: >
lxc-copy --snapshot -B {{ lxc_container_backing_store }}
--name {{ lxc_container_base_name }}
--newname {{ inventory_hostname }}
-L {{ properties.container_fs_size | default(lxc_container_fs_size) }}
--logfile {{ lxc_container_log_path }}/lxc-{{ inventory_hostname }}.log
--logpriority {{ (debug | bool) | ternary('DEBUG', 'INFO') }}
delegate_to: "{{ physical_host }}"
when:
- lxc_container_info.rc != 0
- name: Set the qgroup limits
block:
- name: Set the qgroup size|compression limits on machines
command: "btrfs qgroup limit {{ item }} /var/lib/lxc/{{ inventory_hostname }}"
changed_when: false
delegate_to: "{{ physical_host }}"
with_items:
- "-e {{ nspawn_host_qgroup_space_limit }}"
- "-c {{ nspawn_host_qgroup_compression_limit }}"
when:
- not nspawn_host_machine_quota_disabled
rescue:
- name: Notice regarding quota system
debug:
msg: >-
There was an error processing the setup of qgroups. Check the system
to ensure they're available otherwise disable the quota system by
setting `nspawn_host_machine_quota_disabled` to true.
when:
- lxc_container_backing_store == 'btrfs'