Mayastor Kubectl Plugin

The ‘Mayastor kubectl plugin’ can be used to view and manage Mayastor resources such as nodes, pools and volumes. It is also used for operations such as scaling the replica count of volumes.

Prerequisites

• Ensure that port 30011 is open. This port will be needed by Mayastor kubectl plugin to communicate to REST servers from outside the cluster.

The plugin requires access to the Mayastor REST server for execution. It usually obtains the correct endpoint from the kube-config file on its own. However, if the plugin is unable to access the endpoint, the master nodes's IP needs to be specified manually using the --rest or -r flag. kubectl mayastor [OPTIONS] --rest=http://:30011

Installation

• The Mayastor kubectl plugin is available for the Linux platform. The binary for the plugin can be found here.

• Add the downloaded Mayastor kubectl plugin under $PATH.

To verify the installation, execute:

Command

kubectl mayastor -V

Expected Output

kubectl-plugin 1.0.0

Using Mayastor kubectl plugin

USAGE:
    kubectl-mayastor [OPTIONS] <SUBCOMMAND>

FLAGS:
    -h, --help       Prints help information
    -V, --version    Prints version information

OPTIONS:
    -j, --jaeger <jaeger>      Trace rest requests to the Jaeger endpoint agent
    -o, --output <output>      The Output, viz yaml, json [default: none]  [possible values: yaml, json, none]
    -r, --rest <rest>          The rest endpoint, parsed from KUBECONFIG, if left empty 
    -t, --timeout <timeout>    Timeout for the REST operations [default: 10s]

SUBCOMMANDS:
    get      'Get' resources
    help     Prints this message or the help of the given subcommand(s)
    scale    'Scale' resources

The plugin can be used to get the following resource information:

• Volumes

Command

kubectl mayastor get volumes

Expected Output

ID                                    REPLICAS  TARGET-NODE  ACCESSIBILITY STATUS  SIZE

18e30e83-b106-4e0d-9fb6-2b04e761e18a  4         mayastor-1   nvmf          Online  10485761
0c08667c-8b59-4d11-9192-b54e27e0ce0f  4         mayastor-2   <none>        Online  10485761

• Pools

Command

kubectl mayastor get pools

Expected Output

ID               TOTAL CAPACITY  USED CAPACITY  DISKS                                                     NODE      STATUS  MANAGED

mayastor-pool-1  5360320512      1111490560     aio:///dev/vdb?uuid=d8a36b4b-0435-4fee-bf76-f2aef980b833  kworker1  Online  true
mayastor-pool-2  5360320512      2172649472     aio:///dev/vdc?uuid=bb12ec7d-8fc3-4644-82cd-dee5b63fc8c5  kworker1  Online  true
mayastor-pool-3  5360320512      3258974208     aio:///dev/vdb?uuid=f324edb7-1aca-41ec-954a-9614527f77e1  kworker2  Online  false
    

• Nodes

Command

kubectl mayastor get nodes

Expected Output

ID          GRPC ENDPOINT   STATUS
mayastor-2  10.1.0.7:10124  Online
mayastor-1  10.1.0.6:10124  Online
mayastor-3  10.1.0.8:10124  Online

All the above resource information can be retrieved for a particular resource using its ID. The command to do so is as follows: kubectl mayastor get <resource_name> <resource_id>

The Mayastor kubectl plugin can also be used for performing the following operations:

• Scaling the replica count of a volume

Command

kubectl mayastor scale volume <volume_id> <size>

Expected Output

Volume 0c08667c-8b59-4d11-9192-b54e27e0ce0f Scaled Successfully 🚀

• Retrieving resource specs in any desired format

Command

kubectl mayastor -ojson get <resource_type>

Expected Output

[{"spec":{"num_replicas":2,"size":67108864,"status":"Created","target":{"node":"ksnode-2","protocol":"nvmf"},"uuid":"5703e66a-e5e5-4c84-9dbe-e5a9a5c805db","topology":{"explicit":{"allowed_nodes":["ksnode-1","ksnode-3","ksnode-2"],"preferred_nodes":["ksnode-2","ksnode-3","ksnode-1"]}},"policy":{"self_heal":true}},"state":{"target":{"children":[{"state":"Online","uri":"bdev:///ac02cf9e-8f25-45f0-ab51-d2e80bd462f1?uuid=ac02cf9e-8f25-45f0-ab51-d2e80bd462f1"},{"state":"Online","uri":"nvmf://192.168.122.6:8420/nqn.2019-05.io.openebs:7b0519cb-8864-4017-85b6-edd45f6172d8?uuid=7b0519cb-8864-4017-85b6-edd45f6172d8"}],"deviceUri":"nvmf://192.168.122.234:8420/nqn.2019-05.io.openebs:nexus-140a1eb1-62b5-43c1-acef-9cc9ebb29425","node":"ksnode-2","rebuilds":0,"protocol":"nvmf","size":67108864,"state":"Online","uuid":"140a1eb1-62b5-43c1-acef-9cc9ebb29425"},"size":67108864,"status":"Online","uuid":"5703e66a-e5e5-4c84-9dbe-e5a9a5c805db"}}]

• Retrieving replica topology for specific volumes.

Command

kubectl mayastor get volume-replica-topology <volume_id>

Expected Output

ID                                    NODE      POOL              STATUS
93b1e1e9-ffcd-4c56-971e-294a530ea5cd  ksnode-2  pool-on-ksnode-2  Online
88d89a92-40cf-4147-97d4-09e64979f548  ksnode-3  pool-on-ksnode-3  Online

The plugin requires access to the Mayastor REST server for execution. It gets the master node IP from the kube-config file. In case of any failure, the REST endpoint can be specified using the ‘–rest’ flag.

Limitations:

• The plugin currently does not have authentication support.

• The plugin can operate only over HTTP.

• In the case of a cluster with multiple master nodes, the plugin by default picks up the first master node IP for accessing the REST service. In case the REST service is not accessible using the selected master node IP, the plugin would not be able to pick up an alternate master node IP by default.