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For purposes of automation, it is strongly recommended that users create "version controlled" declarative cluster specification files to provision and manage the lifecycle of Kubernetes clusters.

Important

Users need to use only a single command (rctl apply -f cluster_spec.yaml) for both provisioning and ongoing lifecycle operations. The controller will automatically determine the required changes and seamlessly map them to the associated action (e.g. add nodes, remove nodes, upgrade Kubernetes, update blueprint etc).

Create Cluster

Declarative

You can create an Upstream k8s cluster based on a version controlled cluster spec that you can manage in a Git repository. This enables users to develop automation for reproducible infrastructure.

./rctl apply -f <cluster file name.yaml>

An illustrative example of the split cluster spec YAML file for MKS is shown below

Kubelet Arguments 

apiVersion: infra.k8smgmt.io/v3
kind: Cluster
metadata:
  name: test-mks
  project: defaultproject
  labels:
    check1: value1
    check2: value2
spec:
  blueprint:
    name: default
    version: latest
  config:
    autoApproveNodes: true
    dedicatedMastersEnabled: false
    highAvailability: false
    installerTtl: 365
    kubeletExtraArgs:
      max-pods: "730"
    kubernetesVersion: v1.25.2
    location: sanjose-us
    network:
      cni:
        name: Calico
        version: 3.19.1
      podSubnet: 10.244.0.0/16
      serviceSubnet: 10.96.0.0/12
    nodes:
    - arch: amd64
      hostname: ip-172-31-61-40
      operatingSystem: Ubuntu20.04
      privateip: 172.31.61.40
      kubelet_args:
        max-pods: 6
        <key>:<value>
      roles:
      - Master
      - Worker
      - Storage
      ssh:
        ipAddress: 35.86.208.181
        port: "22"
        privateKeyPath: mks-test.pem
        username: ubuntu
  type: mks

Important

Illustrative examples of "cluster specifications" are available for use in this Public Git Repository.

Extended MKS Configuration Spec

Below is an extended MKS config specification that includes additional parameters to facilitate system synchronization for MKS clusters.

  • systemComponentsPlacement
  • ssh: SSH credentials used by the GitOps Agent to perform actions on the cluster nodes. The cluster-level SSH section provides the option to override node-level SSH settings.
    • port
    • privateKeyPath
    • username
    • passphrase
apiVersion: infra.k8smgmt.io/v3
kind: Cluster
metadata:
  name: demo-v3-cluster
  project: defaultproject
spec:
  blueprint:
    name: minimal
    version: latest
  config:
    autoApproveNodes: true
    highAvailability: true
    kubernetesVersion: v1.28.9
    location: sanjose-us
    ssh:
      privateKeyPath: /home/ubuntu/.ssh/id_rsa
      username: ubuntu
      port: "22"
      passphrase: "test"
    network:
      cni:
        name: Calico
        version: 3.26.1
      podSubnet: 10.244.0.0/16
      serviceSubnet: 10.96.0.0/12
    nodes:
    - arch: amd64
      hostname: demo-mks-node-1
      operatingSystem: Ubuntu20.04
      privateIP: 10.12.48.231
      roles:
      - ControlPlane
      - Worker
      ssh:
        ipAddress: 10.12.54.250        
    - arch: amd64
      hostname: demo-mks-node-2
      operatingSystem: Ubuntu20.04
      privateIP: 10.12.101.17
      roles:
      - ControlPlane
      - Worker
      ssh:
        ipAddress: 10.12.54.251
    - arch: amd64
      hostname: demo-mks-node-3
      operatingSystem: Ubuntu20.04
      privateIP: 10.12.96.235
      roles:
      - ControlPlane
      - Worker
      ssh:
        ipAddress: 10.12.54.252
    - arch: amd64
      hostname: demo-mks-node-w-1
      operatingSystem: Ubuntu20.04
      privateIP: 10.12.16.15
      roles:
      - Worker
      ssh:
        ipAddress: 10.12.54.253
        privateKeyPath: /home/ubuntu/.ssh/anotherkey.pem
  systemComponentsPlacement:
    nodeSelector:
      app: infra
    tolerations:
    - effect: NoSchedule
      key: app
      operator: Equal
      value: infra
  type: mks

Important

  • All fields can be overridden at the node level. This is useful when different SSH keys are used for each node. If an IP address is not provided for SSH, use the private IP to connect to the nodes and run the installer
  • SSH configurations are primarily intended for use with RCTL

Extended MKS Configuration Spec for System Sync Operation

Below is an extended MKS config specification that includes additional parameters to facilitate system synchronization for MKS clusters.

  • dedicatedControlPlane
  • systemComponentsPlacement
  • cloudCredentials
apiVersion: infra.k8smgmt.io/v3
kind: Cluster
metadata:
  name: demo-mks-gitsync-ha-103
  project: defaultproject
spec:
  blueprint:
    name: minimal
    version: latest
  cloudCredentials: demo-mks-ssh-v4
  config:
    autoApproveNodes: true
    dedicatedControlPlane: true
    location: sanjose-us
    controlPlane:
      dedicated: true
      kubernetesVersion: v1.28.6
      highAvailability: true
    addons:
    - type: cni
      name: Calico
      version: 3.26.1
    - type:     
    network:    
      podSubnet: 10.244.0.0/16
      serviceSubnet: 10.96.0.0/12z
    nodes:
    - arch: amd64
      hostname: demo-mks-1
      operatingSystem: Ubuntu20.04
      privateIP: 10.12.4.90
      roles:
      - ControlPlane
    - arch: amd64
      hostname: demo-mks-3
      operatingSystem: Ubuntu20.04
      privateIP: 10.12.101.138
      roles:
      - ControlPlane
      - Worker
    - arch: amd64
      hostname: demo-mks-1
      operatingSystem: Ubuntu20.04
      privateIP: 10.12.33.173
      roles:
      - Worker
      - Master
    - arch: amd64
      hostname: demo-mks-2
      operatingSystem: Ubuntu20.04
      privateIP: 10.12.15.240
      cloudCredentials: demo-mks-ssh-v5
  systemCompenentsPlacement:
    nodeSelector:
      app: infra
    tolerations:
    - effect: NoSchedule
      key: app
      operator: Equal
      value: infra
  ssh:
    ipAddress: 158.101.45.62
    port: "22"
    privateKeyPath: /Users/demo/Desktop/ocikeys/mks2.pem
    username: user1
  proxy: {}
  type: mks

To create a cluster using this extended config spec, run the below command:

./rctl apply -f <cluster file name.yaml> --v3

Conjurer Changes for rctl apply

The below change is only for users who are using the rctl apply path for cluster provisioning.

  • Previous Behavior:

    • Conjurer binaries were stored in the user's home directory.
    • This could lead to file corruption when multiple nodes attempted to write to the same file during rctl apply in environments using NFS volumes.

  • New Behavior:

    • The location of Conjurer binaries has been moved to /usr/bin.
    • This ensures that concurrent writes by multiple nodes no longer cause corruption.

  • Passphrase and Certificate Storage:

    • The passphrase (txt) and certificate (PEM file) are now stored in /tmp.

  • Changes Required:

    • If you use automation scripts with rctl apply that reference the old home directory path, you will need to update the path to /usr/bin for executing the Conjurer when provisioing cluster or removing cluster nodes . This change is necessary to ensure correct execution of the Conjurer binary.

Note: The passphrase and PEM file are stored in the /tmp folder, which will be automatically removed on reboot.

Once the rctl create command is executed successfully, following actions will be done:

  • Create cluster on the controller
  • Download conjurer & credentials
  • SCP conjurer & credentials to node
  • Run conjurer
  • Configure role, interface
  • Start provision

Note

At this time only SSH key based authentication is supportted to scp into the nodes

Provision Status

During cluster provisioning, status can be monitored as shown below.

./rctl get cluster <cluster-name> -o json | jq .status

The above command will return READY when the provision is complete.

Add Nodes

Users can add nodes on the cluster and update the config yaml file with the below command

./rctl apply -f <cluster-filename.yaml>

Example:

Add the below node details in the yaml file under the nodes key

- hostname: rctl-mks-1
  operatingSystem: "Ubuntu18.04"
  arch: amd64
  privateIP: 10.109.23.6
  roles:
    - Worker
    - Storage
  labels:
      key1: value1
      key2: value2
  taints:
    - effect: NoSchedule
      key: app
      value: infra
  ssh:
    privateKeyPath: "ssh-key-2020-11-11.key"
    ipAddress: 10.109.23.6
    userName: ubuntu
    port: 22

Use the below command to update the yaml file and add the nodes to the cluster

./rctl apply -f <cluster_filename.yaml>

Once the rctl update command is executed succesfully, following actions will be done:

  • Download conjurer & credentials
  • SCP conjurer & credentials to node
  • Run conjurer
  • Configure role, interface
  • Start provision

For more examples of MKS cluster spec, refer here

Node Provision Status

Once the node is added, Provision will trigger and provision status can be monitored as shown below.

rctl get cluster <cluster-name> -o json |  jq -r -c '.nodes[] | select(.hostname=="<hostname of the node>") | .status'

The above command will return READY when the provision is complete.

Bulk Node Deletion

The MKS Bulk Node Deletion feature allows for the simultaneous deletion of multiple nodes in a MKS environment, using RCTL. It is recommended to delete up to 100 nodes at a time.

Below is an example of a cluster with 30 nodes:

Retry Provisioning

  • To remove these nodes from the MKS Cluster using RCTL, run the command: ./rctl apply -f <cluster_filename.yaml>. Below is the output of this deletion process
{
        "taskset_id": "dk64021",
        "operations": [
        {
            "operation": "BulkNodeDelete",
            "resource_name": "mks-scale-aug",
            "status": "PROVISION_TASK_STATUS_INPROGRESS"
        }
    ],
    "comments": "Configuration is being applied to the cluster",
     "status": "PROVISION_TASKSET_STATUS_INPROGRESS"
}

Now, the status of all nodes will be Deleting.

Retry Provisioning

  • To check the status of the node deletion operation, run the command using the status id: ./rctl status apply <taskset_id>
  • Once the node(s) deletion is complete, the status will be shown as Deleted

Retry Provisioning

Note: It takes approximately 12 minutes to complete the deletion of 100 nodes.

Force Delete Node

To force delete a node, remove the nodes to be deleted from the cluster configuration and apply the updated configuration using the --force flag, as shown in the command below. This ensures the nodes are deleted immediately, bypassing any validation or blocking errors.

rctl apply -f <cluster_config.yaml> --force

K8s Upgrade Strategy

To upgrade the nodes, incorporate the strategy parameters into the specification, whether opting for a concurrent or sequential approach. Here is an illustrative configuration file where the corresponding parameters have been integrated.

apiVersion: infra.k8smgmt.io/v3
kind: Cluster
metadata:
  name: qc-mks-cluster-1
  project: test-project
spec:
  blueprint:
    name: default
  config:
    autoApproveNodes: true
    kubernetesVersion: v1.30.4
    kubernetesUpgrade:
      strategy: concurrent
      params:
        workerConcurrency: "80%"
    network:
      cni:
        name: Calico
        version: 3.24.5
      ipv6:
        podSubnet: 2001:db8:42:0::/56
        serviceSubnet: 2001:db8:42:1::/112
      podSubnet: 10.244.0.0/16
      serviceSubnet: 10.96.0.0/12
    nodes:
    - arch: amd64
      hostname: mks-node-1
      operatingSystem: Ubuntu20.04
      privateip: 10.0.0.81
      roles:
      - Worker
      - Master
      ssh: {}
    - arch: amd64
      hostname: mks-node-2
      operatingSystem: Ubuntu20.04
      privateip: 10.0.0.155
      roles:
      - Worker
      ssh: {}
    - arch: amd64
      hostname: mks-node-3
      operatingSystem: Ubuntu20.04
      privateip: 10.0.0.169
      roles:
      - Worker
      ssh: {}
    - arch: amd64
      hostname: mks-node-4
      operatingSystem: Ubuntu20.04
      privateip: 10.0.0.196
      roles:
      - Worker
      ssh: {}
    - arch: amd64
      hostname: mks-node-5
      operatingSystem: Ubuntu20.04
      privateip: 10.0.0.115
      roles:
      - Worker
      ssh: {}
    - arch: amd64
      hostname: mks-node-6
      operatingSystem: Ubuntu20.04
      privateip: 10.0.0.159
      roles:
      - Worker
      ssh: {}
    proxy: {}
  type: mks

For the Concurrent strategy, assign a value to workerConcurrency, whereas in the case of the Sequential strategy, workerConcurrency is not required. Refer K8s Upgrade page for more information.

Cordon/Uncordon Nodes

  • Mark the node as unschedulable by running the command
./rctl cordon node <node-name> --cluster <cluster-name>
  • Drain the node to remove all running pods, excluding daemonset pods
./rctl drain node <node-name> --cluster <cluster-name> --ignore-daemonsets --delete-emptydir-data
  • Uncordon the node using the below command
./rctl uncordon node <node-name> --cluster <cluster-name>

Delete Cluster

Users can delete one or more clusters with a single command

./rctl delete cluster <mkscluster-name>

(or)

./rctl delete cluster <mkscluster1-name> <mkscluster2-name>

Dry Run

The dry run command is utilized for operations such as Cluster Provisioning, K8s upgrades, blueprint upgrades, and node operations(e.g. :Node Addition/Node Deletion/Labels/Taints). It provides a pre-execution preview of changes, enabling users to assess potential modifications before implementation. This proactive approach is beneficial for identifying and addressing issues, ensuring that the intended changes align seamlessly with infrastructure requirements. Whether provisioning a new cluster or managing updates, incorporating a dry run enhances the predictability, reliability, and overall stability of your infrastructure.

./rctl apply -f <cluster_filename.yaml> --dry-run

Example

  1. Node Addition - Day 2 operation

Below is an example of the output from the dry run command when a user tries to add a node on Day 2:

./rctl apply -f cluster_file.yaml --dry-run
Running echo $HOSTNAME on 34.211.224.152
Running PATH=$PATH:/usr/sbin ip -f inet addr show on 34.211.224.152
Running command -v bzip2 on 34.211.224.152 to verify if bzip2 is present on node
Running command -v wget on 34.211.224.152 to verify if wget is present on node
{
  "operations": [
    {
      "operation": "NodeAddition",
      "resource_name": "ip-172-31-27-101"
    }
  ]
}

Dry Run Output

  • The output indicates a successful dry run
  • The operation specified is "NodeAddition," indicating the intent to add a node to the cluster

  • The resource_name is "ip-172-31-27-101," representing the hostname or identifier for the node being added

  • Incorrect K8s version - Day 2 operation

Below is an example of the output from the dry run command when a user tries to add an incorrect K8s version:

./rctl apply -f check1.yaml --dry-run
Error: Error performing apply on cluster "mks-test-1-calico": server error [return code: 400]: {"operations":null,"error":{"type":"Processing Error","status":400,"title":"Processing request failed","detail":{"Message":"Kubernetes version v1.28.3 not supported\n"}}}

Dry Run Output

Indicates that an error occurred while trying to apply changes to the cluster named "mks-test-1-calico," and the server returned an HTTP status code 400 (Bad Request).