4.2. Creating a ContainerRuntimeConfig CR to edit CRI-O parameters
You can change some of the settings associated with the OpenShift Container Platform CRI-O runtime for the nodes associated with a specific machine config pool (MCP). Using a ContainerRuntimeConfig custom resource (CR), you set the configuration values and add a label to match the MCP. The MCO then rebuilds the crio.conf and storage.conf configuration files on the associated nodes with the updated values.
To revert the changes implemented by using a ContainerRuntimeConfig CR, you must delete the CR. Removing the label from the machine config pool does not revert the changes.
You can modify the following settings by using a ContainerRuntimeConfig CR:
-
Log level: The
logLevelparameter sets the CRI-Olog_levelparameter, which is the level of verbosity for log messages. The default isinfo(log_level = info). Other options includefatal,panic,error,warn,debug, andtrace. -
Overlay size: The
overlaySizeparameter sets the CRI-O Overlay storage driversizeparameter, which is the maximum size of a container image. -
Container runtime: The
defaultRuntimeparameter sets the container runtime to eithercrunorrunc. The default iscrun.
You should have one ContainerRuntimeConfig CR for each machine config pool with all the config changes you want for that pool. If you are applying the same content to all the pools, you only need one ContainerRuntimeConfig CR for all the pools.
You should edit an existing ContainerRuntimeConfig CR to modify existing settings or add new settings instead of creating a new CR for each change. It is recommended to create a new ContainerRuntimeConfig CR only to modify a different machine config pool, or for changes that are intended to be temporary so that you can revert the changes.
You can create multiple ContainerRuntimeConfig CRs, as needed, with a limit of 10 per cluster. For the first ContainerRuntimeConfig CR, the MCO creates a machine config appended with containerruntime. With each subsequent CR, the controller creates a new containerruntime machine config with a numeric suffix. For example, if you have a containerruntime machine config with a -2 suffix, the next containerruntime machine config is appended with -3.
If you want to delete the machine configs, you should delete them in reverse order to avoid exceeding the limit. For example, you should delete the containerruntime-3 machine config before deleting the containerruntime-2 machine config.
If you have a machine config with a containerruntime-9 suffix, and you create another ContainerRuntimeConfig CR, a new machine config is not created, even if there are fewer than 10 containerruntime machine configs.
Example showing multiple ContainerRuntimeConfig CRs
$ oc get ctrcfg
Example output
NAME AGE
ctr-overlay 15m
ctr-level 5m45s
Example showing multiple containerruntime machine configs
$ oc get mc | grep container
Example output
...
01-master-container-runtime b5c5119de007945b6fe6fb215db3b8e2ceb12511 3.5.0 57m
...
01-worker-container-runtime b5c5119de007945b6fe6fb215db3b8e2ceb12511 3.5.0 57m
...
99-worker-generated-containerruntime b5c5119de007945b6fe6fb215db3b8e2ceb12511 3.5.0 26m
99-worker-generated-containerruntime-1 b5c5119de007945b6fe6fb215db3b8e2ceb12511 3.5.0 17m
99-worker-generated-containerruntime-2 b5c5119de007945b6fe6fb215db3b8e2ceb12511 3.5.0 7m26s
...
The following example sets the log_level field to debug, sets the overlay size to 8 GB, and configures runC as the container runtime:
Example ContainerRuntimeConfig CR
apiVersion: machineconfiguration.openshift.io/v1
kind: ContainerRuntimeConfig
metadata:
name: overlay-size
spec:
machineConfigPoolSelector:
matchLabels:
pools.operator.machineconfiguration.openshift.io/worker: ''
containerRuntimeConfig:
logLevel: debug
overlaySize: 8G
defaultRuntime: "runc"
- 1
- Specifies the machine config pool label. For a container runtime config, the role must match the name of the associated machine config pool.
- 2
- Optional: Specifies the level of verbosity for log messages.
- 3
- Optional: Specifies the maximum size of a container image.
- 4
- Optional: Specifies the container runtime to deploy to new containers, either
crunorrunc. The default value iscrun.
Procedure
To change CRI-O settings using the ContainerRuntimeConfig CR:
Create a YAML file for the
ContainerRuntimeConfigCR:apiVersion: machineconfiguration.openshift.io/v1 kind: ContainerRuntimeConfig metadata: name: overlay-size spec: machineConfigPoolSelector: matchLabels: pools.operator.machineconfiguration.openshift.io/worker: ''1 containerRuntimeConfig:2 logLevel: debug overlaySize: 8G defaultRuntime: "runc"Create the
ContainerRuntimeConfigCR:$ oc create -f <file_name>.yamlVerify that the CR is created:
$ oc get ContainerRuntimeConfigExample output
NAME AGE overlay-size 3m19sCheck that a new
containerruntimemachine config is created:$ oc get machineconfigs | grep containerrunExample output
99-worker-generated-containerruntime 2c9371fbb673b97a6fe8b1c52691999ed3a1bfc2 3.5.0 31sMonitor the machine config pool until all are shown as ready:
$ oc get mcp workerExample output
NAME CONFIG UPDATED UPDATING DEGRADED MACHINECOUNT READYMACHINECOUNT UPDATEDMACHINECOUNT DEGRADEDMACHINECOUNT AGE worker rendered-worker-169 False True False 3 1 1 0 9hVerify that the settings were applied in CRI-O:
Open an
oc debugsession to a node in the machine config pool and runchroot /host.$ oc debug node/<node_name>sh-4.4# chroot /hostVerify the changes in the
crio.conffile:sh-4.4# crio config | grep 'log_level'Example output
log_level = "debug"Verify the changes in the
storage.conffile:sh-4.4# head -n 7 /etc/containers/storage.confExample output
[storage] driver = "overlay" runroot = "/var/run/containers/storage" graphroot = "/var/lib/containers/storage" [storage.options] additionalimagestores = [] size = "8G"Verify the changes in the
crio/crio.conf.d/01-ctrcfg-defaultRuntimefile:sh-5.1# cat /etc/crio/crio.conf.d/01-ctrcfg-defaultRuntimeExample output
[crio] [crio.runtime] default_runtime = "runc"