3.2.3. 在 RHCOS 上启用内核参数的多路径

流程

1. 要在 control plane 节点上启用多路径（也称为 master 节点）：

   • 创建机器配置文件，如 99-master-kargs-mpath.yaml，该文件指示集群添加 master 标签并标识多路径内核参数，例如：

   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

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2. 在 worker 节点上启用多路径：

   • 创建机器配置文件，如 99-worker-kargs-mpath.yaml，该文件指示集群添加 worker 标签并标识多路径内核参数，例如：

     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

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3. 使用之前创建的 master 或 worker YAML 文件创建新机器配置：

   $ oc create -f ./99-master-kargs-mpath.yaml

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4. 检查机器配置以查看是否添加了新配置：

   $ oc get MachineConfig

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   输出示例

   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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5. 检查节点：

   $ oc get nodes

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   输出示例

   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

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   您可以发现，在应用更改时每个 worker 节点上的调度都会被禁用。

6. 前往其中一个 worker 节点并列出内核命令行参数（主机上的 /proc/cmdline 中），以检查内核参数确实已发挥作用：

   $ oc debug node/ip-10-0-141-105.ec2.internal

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   输出示例

   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

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   您应该看到添加的内核参数。