tripleo-docs/deploy-guide/source/features/deployed_ceph.rst

Deployed Ceph

In Wallaby and newer it is possible to provision hardware and deploy Ceph before deploying the overcloud on the same hardware.

Deployed Ceph Workflow

As described in the ../deployment/network_v2 the overcloud deploy command was extended so that it can run all of the following as separate steps:

1. Create Networks
2. Create Virtual IPs
3. Provision Baremetal Instances
4. Deploy Ceph
5. Create the overcloud Ephemeral Heat stack
6. Run Config-Download and the deploy-steps playbook

This document covers the "Deploy Ceph" step above. For details on the other steps see ../deployment/network_v2.

The "Provision Baremetal Instances" step outputs a YAML file describing the deployed baremetal, for example:

openstack overcloud node provision \
        -o ~/deployed_metal.yaml \
        ...

The deployed_metal.yaml file can be passed as input to the openstack overcloud ceph deploy command, which in turn outputs a YAML file describing the deployed Ceph cluster, for example:

openstack overcloud ceph deploy \
        ~/deployed_metal.yaml \
        -o ~/deployed_ceph.yaml \
        ...

Both the deployed_metal.yaml and deployed_ceph.yaml files may then be passed as input to the step to "Create the overcloud Ephemeral Heat stack", for example:

openstack overcloud deploy --templates \
        -e ~/deployed_metal.yaml \
        -e ~/deployed_ceph.yaml \
        ...

While the overcloud is being deployed the data in the deployed_ceph.yaml file will be used to configure the OpenStack clients to connect to the Ceph cluster as well as configure the Ceph cluster to host OpenStack.

The above workflow is called "Deployed Ceph" because Ceph is already deployed when the overcloud is configured.

Deployed Ceph Scope

The "Deployed Ceph" feature deploys a Ceph cluster ready to serve RBD by calling the same TripleO Ansible roles described in cephadm. When the "Deployed Ceph" process is over you should expect to find the following:

• The CephMon, CephMgr, and CephOSD services are running on all nodes which should have those services
• It's possible to SSH into a node with the CephMon service and run sudo cepham shell
• All OSDs should be running unless there were environmental issues (e.g. disks were not cleaned)
• A ceph configuration file and client admin keyring file in /etc/ceph of overcloud nodes with the CephMon service
• The Ceph cluster is ready to serve RBD

You should not expect the following after "Deployed Ceph" has run:

• No pools or cephx keys for OpenStack will be created yet
• No CephDashboard, CephRGW or CephMds services will be running yet

The above will be configured during overcloud deployment by the openstack overcloud deploy command as they were prior to the "Deployed Ceph" feature. The reasons for this are the following:

• The Dashboard and RGW services need to integrate with haproxy which is deployed with the overcloud
• The list of pools to create and their respective cephx keys are a function of which OpenStack clients (e.g. Nova, Cinder, etc) will be used so they must be in the overcloud definition. Thus, they are created during overcloud deployment

During the overcloud deployment the above resources will be created in Ceph by the TripleO Ansible roles described in cephadm using the client admin keyring file and the ~/deployed_ceph.yaml file output by openstack overcloud ceph deploy. Because these resources are created directly on the Ceph cluster with admin level access, "Deployed Ceph" is different from the "External Ceph" feature described in ceph_external.

The main benefits of using "Deployed Ceph" are the following:

• Use cephadm to deploy Ceph on the hardware managed by TripleO without having to write your own cephadm spec file (though you may provide your own if you wish)
• Focus on debugging the basic Ceph deployment without debugging the overcloud deployment at the same time
• Fix any Ceph deployment problems directly using either Ansible or the Ceph orchestrator tools before starting the overcloud deployment
• Have the benefits above while maintaining hyperconverged support by using a tested workflow

In summary, openstack overcloud ceph deploy deploys the Ceph cluster while openstack overcloud deploy (and the commands that follow) deploy OpenStack and configure that Ceph cluster to be used by OpenStack.

Deployed Ceph Command Line Interface

The command line interface supports the following options:

$ openstack overcloud ceph deploy --help
usage: openstack overcloud ceph deploy [-h] -o <deployed_ceph.yaml> [-y]
                                       [--stack STACK]
                                       [--working-dir WORKING_DIR]
                                       [--roles-data ROLES_DATA]
                                       [--ceph-spec CEPH_SPEC | --osd-spec OSD_SPEC]
                                       [--crush-hierarchy CEPH_CRUSH_HIERARCHY]
                                       [--container-image-prepare CONTAINER_IMAGE_PREPARE]
                                       [--container-namespace CONTAINER_NAMESPACE]
                                       [--container-image CONTAINER_IMAGE]
                                       [--container-tag CONTAINER_TAG]
                                       [--registry-url REGISTRY_URL]
                                       [--registry-username REGISTRY_USERNAME]
                                       [--registry-password REGISTRY_PASSWORD]
                                       <deployed_baremetal.yaml>

positional arguments:
  <deployed_baremetal.yaml>
                        Path to the environment file output from "openstack
                        overcloud node provision".

optional arguments:
  -h, --help            show this help message and exit
  -o <deployed_ceph.yaml>, --output <deployed_ceph.yaml>
                        The path to the output environment file describing the
                        Ceph deployment to pass to the overcloud deployment.
  -y, --yes             Skip yes/no prompt before overwriting an existing
                        <deployed_ceph.yaml> output file (assume yes).
  --stack STACK         Name or ID of heat stack (default=Env:
                        OVERCLOUD_STACK_NAME)
  --working-dir WORKING_DIR
                        The working directory for the deployment where all
                        input, output, and generated files will be stored.
                        Defaults to "$HOME/overcloud-deploy/<stack>"
  --roles-data ROLES_DATA
                        Path to an alternative roles_data.yaml. Used to decide
                        which node gets which Ceph mon, mgr, or osd service
                        based on the node's role in <deployed_baremetal.yaml>.
  --ceph-spec CEPH_SPEC
                        Path to an existing Ceph spec file. If not provided a
                        spec will be generated automatically based on --roles-
                        data and <deployed_baremetal.yaml>
  --osd-spec OSD_SPEC   Path to an existing OSD spec file. Mutually exclusive
                        with --ceph-spec. If the Ceph spec file is generated
                        automatically, then the OSD spec in the Ceph spec file
                        defaults to {data_devices: {all: true}} for all
                        service_type osd. Use --osd-spec to override the
                        data_devices value inside the Ceph spec file.
  --crush-hierarchy CRUSH_HIERARCHY_SPEC
                        Path to an existing Ceph crush hierarchy spec file that
                        describes the custom osd location according to the Ceph
                        specification.
  --container-image-prepare CONTAINER_IMAGE_PREPARE
                        Path to an alternative
                        container_image_prepare_defaults.yaml. Used to control
                        which Ceph container is pulled by cephadm via the
                        ceph_namespace, ceph_image, and ceph_tag variables in
                        addition to registry authentication via
                        ContainerImageRegistryCredentials.

container-image-prepare overrides:
  The following options may be used to override individual values set via
  --container-image-prepare. If the example variables below were set the
  image would be concatenated into quay.io/ceph/ceph:latest and a custom
  registry login would be used.

  --container-namespace CONTAINER_NAMESPACE
                        e.g. quay.io/ceph
  --container-image CONTAINER_IMAGE
                        e.g. ceph
  --container-tag CONTAINER_TAG
                        e.g. latest
  --registry-url REGISTRY_URL
  --registry-username REGISTRY_USERNAME
  --registry-password REGISTRY_PASSWORD

This command is provided by the python-tripleoclient plugin.
$

Run openstack overcloud ceph deploy --help in your own environment to see the latest options which you have available.

Ceph Configuration Options

The deployed_ceph.yaml Heat environment file output by openstack overcloud ceph deploy has ApplyCephConfigOverridesOnUpdate set to true. This means that services not covered by deployed ceph, e.g. RGW, can have the configuration changes that they need applied during overcloud deployment. After the deployed ceph process has run and then after the overcloud is deployed, it is recommended to update the deployed_ceph.yaml Heat environment file, or similar, to set ApplyCephConfigOverridesOnUpdate to false. Any subsequent Ceph configuration changes should then be made by the ceph config command. For more information on the CephConfigOverrides and ApplyCephConfigOverridesOnUpdate parameters see cephadm.

Ceph Spec Options

The roles file, described in the next section, and the output of openstack overcloud node provision are passed to the ceph_spec_bootstrap Ansible module to create a Ceph Service Specification. The openstack overcloud ceph deploy command does this automatically so it is not necessary to use the options described in this section unless desired.

It's possible to generate a Ceph Spec on the undercloud before deployment by using the ceph_spec_bootstrap Ansible module directly, for example:

ansible localhost -m ceph_spec_bootstrap \
        -a deployed_metalsmith=deployed_metal.yaml

By default the above creates the file ~/ceph_spec.yaml. For more information on the ceph_spec_bootstrap module run ansible-doc ceph_spec_bootstrap. The spec file may then be edited if desired and passed directly like this:

openstack overcloud ceph deploy \
        deployed_metal.yaml \
        -o deployed_ceph.yaml \
        --ceph-spec ~/ceph_spec.yaml

All available disks (excluding the disk where the operating system is installed) are used as OSDs as per the following default inside the ceph spec:

data_devices:
  all: true

In the above example, the data_devices key is valid for any Ceph Service Specification whose service_type is "osd". Other OSD service types, as found in the Advanced OSD Service Specifications, may be set by using the --osd-spec option.

If the file osd_spec.yaml contains the following:

data_devices:
  rotational: 1
db_devices:
  rotational: 0

and the following command is run:

openstack overcloud ceph deploy \
        deployed_metal.yaml \
        -o deployed_ceph.yaml \
        --osd-spec osd_spec.yaml

Then all rotating devices will be data devices and all non-rotating devices will be used as shared devices (wal, db). This is because when the dynamic Ceph service specification is built whatever is in the file referenced by --osd-spec will be appended to the section of the specification if the service_type is "osd".

Crush Hierarchy Options

As described in the previous section, the ceph_spec_bootstrap Ansible module is used to generate the Ceph related spec file which is applied using the Ceph orchestrator tool. During the Ceph OSDs deployment, a custom crush hierarchy can be defined and passed using the --crush-hierarchy option. As per Ceph Host Management, by doing this the location attribute is added to the Hosts spec. The location attribute will only affect the initial CRUSH location Subsequent changes of the location property will be ignored. Also, removing a host will not remove any CRUSH generated bucket.

Example: Apply a custom crush hierarchy to the deployed OSDs

If the file crush_hierarchy.yaml contains something like the following:

---
ceph-0:
  root: default
  rack: r0
ceph-1:
  root: default
  rack: r1
ceph-2:
  root: default
  rack: r2

and the following command is run:

openstack overcloud ceph deploy \
        deployed_metal.yaml \
        -o deployed_ceph.yaml \
        --osd-spec osd_spec.yaml \
        --crush-hierarchy crush_hierarchy.yaml

Then the Ceph cluster will bootstrap with the following Ceph OSD layout:

[ceph: root@ceph-0 /]# ceph osd tree
ID  CLASS  WEIGHT   TYPE NAME                  STATUS  REWEIGHT  PRI-AFF
-1         0.02939  root default
-3         0.00980      rack r0
-2         0.00980          host ceph-node-00
 0    hdd  0.00980              osd.0              up   1.00000  1.00000
-5         0.00980      rack r1
-4         0.00980          host ceph-node-01
 1    hdd  0.00980              osd.1              up   1.00000  1.00000
-7         0.00980      rack r2
-6         0.00980          host ceph-node-02
 2    hdd  0.00980              osd.2              up   1.00000  1.00000

Note

Device classes are automatically detected by Ceph, but crush rules are associated to pools and they still be defined using the CephCrushRules parameter during the overcloud deployment. Additional details can be found in the Overriding crush rules section.

Service Placement Options

The Ceph services defined in the roles_data.yaml file as described in composable_services determine which baremetal node runs which service. By default the Controller role has the CephMon and CephMgr service while the CephStorage role has the CephOSD service. Most composable services require Heat output in order to determine how services are configured, but not the Ceph services. Thus, the roles_data.yaml file remains authoritative for Ceph service placement even though the "Deployed Ceph" process happens before Heat is run.

It is only necessary to use the --roles-file option if the default roles_data.yaml file is not being used. For example if you intend to deploy hyperconverged nodes, then you want the predeployed compute nodes to be in the ceph spec with the "osd" label and for the service_type "osd" to have a placement list containing a list of the compute nodes. To do this generate a custom roles file as described in composable_services like this:

openstack overcloud roles generate Controller ComputeHCI > custom_roles.yaml

and then pass that roles file like this:

openstack overcloud ceph deploy \
        deployed_metal.yaml \
        -o deployed_ceph.yaml \
        --roles-data custom_roles.yaml

After running the above the compute nodes should have running OSD containers and when the overcloud is deployed Nova compute services will then be set up on the same hosts.

If you wish to generate the ceph spec with the modified placement described above before the ceph deployment, then the same file may be passed to a direct call of the ceph_spec_bootstrap ansible module:

ansible localhost -m ceph_spec_bootstrap \
  -a "deployed_metalsmith=deployed_metal.yaml tripleo_roles=custom_roles.yaml"

Network Options

The storage networks defined in the network_data.yaml file as described in custom_networks determine which networks Ceph is configured to use. When using network isolation, the standard is for TripleO to deploy two storage networks which map to the two Ceph networks in the following way:

• storage - Storage traffic, the Ceph public_network, e.g. Nova compute nodes use this network for RBD traffic to the Ceph cluster.
• storage_mgmt - Storage management traffic (such as replication traffic between storage nodes), the Ceph cluster_network, e.g. Ceph OSDs use this network to replicate data.

openstack overcloud ceph deploy will use the network_data.yaml file specified by the --network-data option to determine which networks should be used for the public_network and cluster_network. It assumes these networks are named storage and storage_mgmt in the network_data.yaml file unless a different name should be used as indicated by the --public-network-name and --cluster-network-name options.

It is necessary to use the --network-data option when deploying with network isolation. Otherwise the default network, i.e. the ctlplane network on the undercloud (192.168.24.0/24), will be used for both the public_network and cluster_network.

Example: Multiple subnets with custom network names

If network_data.yaml contains the following:

- name: StorageMgmtCloud0
  name_lower: storage_mgmt_cloud_0
  service_net_map_replace: storage_mgmt
  subnets:
    storage_mgmt_cloud_0_subnet12:
      ip_subnet: '172.16.12.0/24'
    storage_mgmt_cloud_0_subnet13:
      ip_subnet: '172.16.13.0/24'
- name: StorageCloud0
  name_lower: storage_cloud_0
  service_net_map_replace: storage
  subnets:
    storage_cloud_0_subnet14:
      ip_subnet: '172.16.14.0/24'
    storage_cloud_0_subnet15:
      ip_subnet: '172.16.15.0/24'

Then the Ceph cluster will have the following parameters set:

[global]
public_network = '172.16.14.0/24,172.16.15.0/24'
cluster_network = '172.16.12.0/24,172.16.13.0/24'
ms_bind_ipv4 = True
ms_bind_ipv6 = False

This is because the TripleO client will see that though the name_lower value does not match storage or storage_mgmt (they match the custom names storage_cloud_0 and storage_mgmt_cloud_0 instead), those names do match the service_net_map_replace values. If service_net_map_replace is in the network_data.yaml, then it is not necessary to use the --public-network-name and --cluster-network-name options. Alternatively the service_net_map_replace key could have been left out and the --public-network-name and --cluster-network-name options could have been used instead. Also, because multiple subnets are used they are concatenated and it is assumed that there is routing between the subnets. If there was no subnets key, in the network_data.yaml file, then the client would have looked instead for the single ip_subnet key for each network.

By default the Ceph global ms_bind_ipv4 is set true and ms_bind_ipv6 is set false.

Example: IPv6

If network_data.yaml contains the following:

- name: Storage
  ipv6: true
  ipv6_subnet: fd00:fd00:fd00:3000::/64
  name_lower: storage
- name: StorageMgmt
  ipv6: true
  ipv6_subnet: fd00:fd00:fd00:4000::/64
  name_lower: storage_mgmt

Then the Ceph cluster will have the following parameters set:

[global]
public_network = fd00:fd00:fd00:3000::/64
cluster_network = fd00:fd00:fd00:4000::/64
ms_bind_ipv4 = False
ms_bind_ipv6 = True

Because the storage networks in network_data.yaml contain ipv6: true, the ipv6_subet values are extracted and the Ceph globals ms_bind_ipv4 is set false and ms_bind_ipv6 is set true. It is not supported to have the public_network use IPv4 and the cluster_network use IPv6 or vice versa.

Example: Directly setting network and ms_bind options

If the examples above are not sufficient for your Ceph network needs, then it's possible to create an initial-ceph.conf with the four parameters public_network, cluster_network, ms_bind_ipv4, and ms_bind_ipv6 options set to whatever values are desired.

When using the --config option it is still important to ensure the TripleO storage and storage_mgmt network names map to the correct public_network and cluster_network so that the rest of the deployment is consistent.

The four parameters, public_network, cluster_network, ms_bind_ipv4, and ms_bind_ipv6, are always set in the Ceph cluster (with ceph config set global) from the --network-data file unless those parameters are explicitly set in the --config file. In that case the values in the --network-data file are not set directly in the Ceph cluster though other aspects of the overcloud deployment treat the --network-data file as authoritative (e.g. when Ceph RGW is set) so both sources should be consistent if the --config file has any of these four parameters.

An example of setting the four parameters in the initial Ceph configuration is below:

$ cat <<EOF > initial-ceph.conf
[global]
public_network = 'fd00:fd00:fd00:3000::/64,172.16.14.0/24'
cluster_network = 'fd00:fd00:fd00:4000::/64,172.16.12.0/24'
ms_bind_ipv4 = true
ms_bind_ipv6 = true
EOF
$ openstack overcloud ceph deploy \
  --config initial-ceph.conf --network-data network_data.yaml

The above assumes that network_data.yaml contains the following:

- name: Storage
  ipv6_subnet: fd00:fd00:fd00:3000::/64
  ip_subnet: 172.16.14.0/24
  name_lower: storage
- name: StorageMgmt
  ipv6_subnet: fd00:fd00:fd00:4000::/64
  ip_subnet: 172.16.12.0/24
  name_lower: storage_mgmt

The above settings, which mix IPv4 and IPv6, are experimental and untested.

Container Options

As described in ../deployment/container_image_prepare the undercloud may be used as a container registry for ceph containers and there is a supported syntax to download containers from authenticated registries. By default openstack overcloud ceph deploy will pull the Ceph container in the default container_image_prepare_defaults.yaml file. The version of the Ceph used in each OpenStack release changes per release and can be seen by running a command like this:

egrep "ceph_namespace|ceph_image|ceph_tag" \
  /usr/share/tripleo-common/container-images/container_image_prepare_defaults.yaml

The --container-image-prepare option can be used to override which container_image_prepare_defaults.yaml file is used. If a version of this file called custom_container_image_prepare.yaml is modified to contain syntax like the following:

ContainerImageRegistryCredentials:
  quay.io/ceph-ci:
    quay_username: quay_password

Then when a command like the following is run:

openstack overcloud ceph deploy \
        deployed_metal.yaml \
        -o deployed_ceph.yaml \
        --container-image-prepare custom_container_image_prepare.yaml

The credentials will be extracted from the file and the tripleo ansible role to bootstrap Ceph will be executed like this:

cephadm bootstrap
 --registry-url quay.io/ceph-ci
 --registry-username quay_username
 --registry-password quay_password
 ...

The syntax of the container image prepare file can also be ignored and instead the following command line options may be used instead:

--container-namespace CONTAINER_NAMESPACE
                      e.g. quay.io/ceph
--container-image CONTAINER_IMAGE
                      e.g. ceph
--container-tag CONTAINER_TAG
                      e.g. latest
--registry-url REGISTRY_URL
--registry-username REGISTRY_USERNAME
--registry-password REGISTRY_PASSWORD

If a variable above is unused, then it defaults to the ones found in the default container_image_prepare_defaults.yaml file. In other words, the above options are overrides.