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Bug 1886229 - Make multipath docs platform-agnostic
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,134 @@ | ||
| // Module included in the following assemblies: | ||
| // | ||
| // * post_installation_configuration/machine-configuration-tasks.adoc | ||
|
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| [id="rhcos-enabling-multipath_{context}"] | ||
| = Enabling multipathing with kernel arguments on {op-system} | ||
|
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| {op-system} supports multipathing on the primary disk, allowing stronger resilience to hardware failure to achieve higher host availability. | ||
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| [IMPORTANT] | ||
| ==== | ||
| Multipathing is only supported when it is activated using the machine config as documented in the following procedure. It must be enabled after {op-system} installation. | ||
| ==== | ||
|
|
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| .Prerequisites | ||
| * You have a running {product-title} cluster that uses version 4.7 or later. | ||
| * You are logged in to the cluster as a user with administrative privileges. | ||
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| .Procedure | ||
|
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| . To enable multipathing on master nodes: | ||
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| * Create a machine config file, such as `99-master-kargs-mpath.yaml`, that instructs the cluster to add the `master` label and that identifies the multipath kernel argument, for example: | ||
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| + | ||
| [source,yaml] | ||
| ---- | ||
| apiVersion: machineconfiguration.openshift.io/v1 | ||
| kind: MachineConfig | ||
| metadata: | ||
| labels: | ||
| machineconfiguration.openshift.io/role: "master" | ||
| name: 99-master-kargs-mpath | ||
| spec: | ||
| kernelArguments: | ||
| - 'rd.multipath=default' | ||
| - 'root=/dev/disk/by-label/dm-mpath-root' | ||
| ---- | ||
|
|
||
| . To enable multipathing on worker nodes: | ||
|
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| * Create a machine config file, such as `99-worker-kargs-mpath.yaml`, that instructs the cluster to add the `worker` label and that identifies the multipath kernel argument, for example: | ||
| + | ||
| [source,yaml] | ||
| ---- | ||
| apiVersion: machineconfiguration.openshift.io/v1 | ||
| kind: MachineConfig | ||
| metadata: | ||
| labels: | ||
| machineconfiguration.openshift.io/role: "worker" | ||
| name: 99-worker-kargs-mpath | ||
| spec: | ||
| kernelArguments: | ||
| - 'rd.multipath=default' | ||
| - 'root=/dev/disk/by-label/dm-mpath-root' | ||
| ---- | ||
|
|
||
| . Create the new machine config by using either the master or worker YAML file you previously created: | ||
| + | ||
| [source,terminal] | ||
| ---- | ||
| $ oc create -f ./99-master-kargs-mpath.yaml | ||
| ---- | ||
|
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| . Check the machine configs to see that the new one was added: | ||
| + | ||
| [source,terminal] | ||
| ---- | ||
| $ oc get MachineConfig | ||
| ---- | ||
| + | ||
| .Example output | ||
| [source,terminal] | ||
| ---- | ||
| NAME GENERATEDBYCONTROLLER IGNITIONVERSION AGE | ||
| 00-master 52dd3ba6a9a527fc3ab42afac8d12b693534c8c9 3.2.0 33m | ||
| 00-worker 52dd3ba6a9a527fc3ab42afac8d12b693534c8c9 3.2.0 33m | ||
| 01-master-container-runtime 52dd3ba6a9a527fc3ab42afac8d12b693534c8c9 3.2.0 33m | ||
| 01-master-kubelet 52dd3ba6a9a527fc3ab42afac8d12b693534c8c9 3.2.0 33m | ||
| 01-worker-container-runtime 52dd3ba6a9a527fc3ab42afac8d12b693534c8c9 3.2.0 33m | ||
| 01-worker-kubelet 52dd3ba6a9a527fc3ab42afac8d12b693534c8c9 3.2.0 33m | ||
| 99-master-kargs-mpath 52dd3ba6a9a527fc3ab42afac8d12b693534c8c9 3.2.0 105s | ||
| 99-master-generated-registries 52dd3ba6a9a527fc3ab42afac8d12b693534c8c9 3.2.0 33m | ||
| 99-master-ssh 3.2.0 40m | ||
| 99-worker-generated-registries 52dd3ba6a9a527fc3ab42afac8d12b693534c8c9 3.2.0 33m | ||
| 99-worker-ssh 3.2.0 40m | ||
| rendered-master-23e785de7587df95a4b517e0647e5ab7 52dd3ba6a9a527fc3ab42afac8d12b693534c8c9 3.2.0 33m | ||
| rendered-worker-5d596d9293ca3ea80c896a1191735bb1 52dd3ba6a9a527fc3ab42afac8d12b693534c8c9 3.2.0 33m | ||
| ---- | ||
|
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| . Check the nodes: | ||
| + | ||
| [source,terminal] | ||
| ---- | ||
| $ oc get nodes | ||
| ---- | ||
| + | ||
| .Example output | ||
| [source,terminal] | ||
| ---- | ||
| NAME STATUS ROLES AGE VERSION | ||
| ip-10-0-136-161.ec2.internal Ready worker 28m v1.20.0 | ||
| ip-10-0-136-243.ec2.internal Ready master 34m v1.20.0 | ||
| ip-10-0-141-105.ec2.internal Ready,SchedulingDisabled worker 28m v1.20.0 | ||
| ip-10-0-142-249.ec2.internal Ready master 34m v1.20.0 | ||
| ip-10-0-153-11.ec2.internal Ready worker 28m v1.20.0 | ||
| ip-10-0-153-150.ec2.internal Ready master 34m v1.20.0 | ||
| ---- | ||
| + | ||
| You can see that scheduling on each worker node is disabled as the change is being applied. | ||
|
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| . Check that the kernel argument worked by going to one of the worker nodes and listing | ||
| the kernel command line arguments (in `/proc/cmdline` on the host): | ||
| + | ||
| [source,terminal] | ||
| ---- | ||
| $ oc debug node/ip-10-0-141-105.ec2.internal | ||
| ---- | ||
| + | ||
| .Example output | ||
| [source,terminal] | ||
| ---- | ||
| Starting pod/ip-10-0-141-105ec2internal-debug ... | ||
| To use host binaries, run `chroot /host` | ||
| sh-4.2# cat /host/proc/cmdline | ||
| ... | ||
| rd.multipath=default root=/dev/disk/by-label/dm-mpath-root | ||
| ... | ||
| sh-4.2# exit | ||
| ---- | ||
| + | ||
| You should see the added kernel arguments. |
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