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ECD Patch is meant to provide a flexible option for users to define and provision Kubernetes objects that suits their system architecture or to tailor the ECD to their preferred flavour.

...

Code Block

services:
    - spec:
        type: ClusterIP
        ports:
          - port: 9092
            protocol: TCP
            targetPort: 9092
      ...
      ...
      patchType: "application/strategic-merge-patch+json"
      patch: |
        spec:
          ports:
            - name: "port-1"
              port: 9093
              protocol: TCP
              targetPort: 9093
            - name: "port-2"
              port: 9094
              protocol: UDP
              targetPort: 9094
          ...

Samples

To help users to understand better, below are some samples that can get users started using ECD patch. Do note that “Before” is based on the ECD - which is the definition file for the desired state. while “After” is based on the conversion and logic processing done by Operator - which is the actual objects provisioning yaml to be applied to the cluster. As you might notice, there are a lot more objects that will be provisioned and handled by Operator itself.

Changing Rollout Strategy

Basically, an ECD will resulting in creating different K8S objects, 1 of them is Deployment object. The rollout strategy is default to RollingUpdate, through ECD patch we can change it to other strategy such as Recreate. The change can be seen on the spec.strategy.typeon After ECD Patch.

Before ECD Patch

After ECD Patch

k apply -f file.yaml

Code Block

apiVersion: mz.digitalroute.com/v1alpha1
kind: ECDeployment
metadata:
  name: ecd-test-rolling-strategy
spec:
  enabled: true
  patchType: "application/strategic-merge-patch+json"
  patch: |
    spec:
      strategy:
        type: Recreate
  image: dtr.digitalroute.com/dr/mz10:10.1.0.0-dev-20200813052033.a224284-ec
  workflows:
  - template: Default.http2
    instances:
      - name: server-1
        parameters: |
          {
            "port": 8989
          }

k get deploy ecd-test-rolling-strategy -o yaml

Code Block

apiVersion: apps/v1
kind: Deployment
metadata:
  ...
  ...
spec:
  progressDeadlineSeconds: 600
  replicas: 1
  revisionHistoryLimit: 10
  selector:
    matchLabels:
      app: ecd-test-rolling-strategy
  strategy:
    type: Recreate
  template:
    ...
    ...

Setting Toleration

In example below, assuming a 3 nodes implementation K8S cluster, 2 nodes are tainted color=blue and 1 node is tainted color=red, the test is to add toleration to ECD so that it will get deployed into node tainted with color=red.

...

Before ECD Patch

After ECD Patch

k apply -f file.yaml

Code Block

apiVersion: mz.digitalroute.com/v1alpha1
kind: ECDeployment
metadata:
  name: ecd-test-tolerations
spec:
  enabled: true
  patchType: "application/strategic-merge-patch+json"
  patch: |
    spec:                                 # Spec for Deployment
      template:                           # Template for Pods
        spec:                             # Spec for Pods
          tolerations:                    # Toleration added to each Pod
          - key: "color"
            value: "red"                  
            operator: "Equal"
            effect: "NoSchedule"
  image: dtr.digitalroute.com/dr/mz10:10.1.0.0-dev-20200813052033.a224284-ec
  workflows:
  - template: Default.http2
    instances:
      - name: server-1
        parameters: |
          {
            "port": 8989
          }

k get pods ecd-test-tolerations-5d646c45cd-g9x8n -o wide

Code Block
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES ecd-test-tolerations-5d646c45cd-g9x8n 1/1 Running 0 80s 10.244.2.10 kl-kube-node03.digitalroute.com <none> <none>

k describe pods ecd-test-tolerations-5d646c45cd-g9x8n| grep -i toleration

Code Block

Name:         ecd-test-tolerations-5d646c45cd-g9x8n
Labels:       ECDeployment=ecd-test-tolerations
              app=ecd-test-tolerations
Controlled By:  ReplicaSet/ecd-test-tolerations-5d646c45cd
  ecd-test-tolerations:
Tolerations:     color=red:NoSchedule
  Normal   Scheduled  5m21s  default-scheduler                         Successfully assigned castle-black/ecd-test-tolerations-5d646c45cd-g9x8n to kl-kube-node03.digitalroute.com
  Normal   Created    5m21s  kubelet, kl-kube-node03.digitalroute.com  Created container ecd-test-tolerations
  Normal   Started    5m20s  kubelet, kl-kube-node03.digitalroute.com  Started container ecd-test-tolerations

Setting Environment Variable

There might be a case where you would like to add in an environment variable. In the example below, we will add one calls ENV where the value will be “dev”.

Before ECD Patch

After ECD Patch

k apply -f file.yaml

Code Block

apiVersion: mz.digitalroute.com/v1alpha1
kind: ECDeployment
metadata:
  name: ecd-test-2
spec:
  enabled: true
  patchType: "application/strategic-merge-patch+json"
  patch: |
    spec:  
      template:              
        spec:     
          containers:
          - name: ecd-test-2
            env:
            - name: ENV 
              value: dev
  image: dtr.digitalroute.com/dr/mz10:10.1.0.0-dev-20200813052033.a224284-ec
  workflows:
  - template: Default.http2
    instances:
      - name: server-1
        parameters: |
          {
            "port": 8989
          }

kex ecd-test-2-7487469546-s77xx bash -- printenv | grep ENV

Code Block
ENV=dev

k describe pods ecd-test-2-7487469546-s77xx

Code Block

Name:         ecd-test-2-7487469546-s77xx
Namespace:    castle-black
Priority:     0
Node:         kl-kube-node03.digitalroute.com/10.60.10.143
Start Time:   Tue, 25 Aug 2020 17:05:04 +0800
Labels:       ECDeployment=ecd-test-2
              app=ecd-test-2
              pod-template-hash=7487469546
Annotations:  Status:  Running
IP:           10.244.2.14
IPs:
  IP:           10.244.2.14
Controlled By:  ReplicaSet/ecd-test-2-7487469546
Containers:
  ecd-test-2:
    Container ID:  docker://a07de37d1cfff80b7ce240d7a6d3821cea393a49b58f8a9f43f97a229efd236f
    Image:         dtr.digitalroute.com/dr/mz10:10.1.0.0-dev-20200813052033.a224284-ec
    Image ID:      docker-pullable://dtr.digitalroute.com/dr/mz10@sha256:6e5efb5bb8e526679d2e0878f5cf69011d0f8724be1dc90f26e631f33afe8227
    Port:          <none>
    Host Port:     <none>
    Command:
      /opt/mz/entrypoint/docker-entrypoint.sh
    Args:
      -e accepts.any.scheduling.criteria=false
    State:          Running
      Started:      Tue, 25 Aug 2020 17:05:05 +0800
    Ready:          True
    Restart Count:  0
    Liveness:       http-get http://:9090/health/live delay=90s timeout=10s period=15s #success=1 #failure=3
    Readiness:      http-get http://:9090/health/ready delay=0s timeout=1s period=5s #success=1 #failure=60
    Environment:
      ENV:  dev
      TZ:   UTC

Mounting a storage

In this scenario, we might want to attach a storage (be it temporary or permanent) in the ECD Pods, perhaps for Batch workflow processing files. In below example, we are attaching a temporary storage (live as long as Pod’s lifespan) and mounting it to the pod.

Before ECD Patch

After ECD Patch

k apply -f file.yaml

Code Block

apiVersion: mz.digitalroute.com/v1alpha1
kind: ECDeployment
metadata:
  name: ecd-test-2
spec:
  enabled: true
  patchType: "application/strategic-merge-patch+json"
  patch: |
    spec:  
      template:              
        spec:     
          containers:
          - name: ecd-test-2
            volumeMounts:
            - mountPath: /cdr_volume
              name: cdr-volume
          volumes:
          - name: cdr-volume
            emptyDir: {}
  image: dtr.digitalroute.com/dr/mz10:10.2.0-xe-2080-bugfix-latest-ec
  workflows:
  - template: Default.http2
    instances:
      - name: server-1
        parameters: |
          {
            "port": 8989
          }

kg pods ecd-test-2-678ccb76d6-s49ql -o yaml

Code Block

apiVersion: v1
kind: Pod
metadata:
  ...
  ...
  name: ecd-test-2-678ccb76d6-s49ql
  ...
  ...
spec:
  containers:
  - name: ecd-test-2
    ...
    ...
    volumeMounts:
    - mountPath: /cdr_volume
      name: cdr-volume
    - mountPath: /etc/config/common
      name: common-config
    - mountPath: /var/run/secrets/kubernetes.io/serviceaccount
      name: default-token-4dc54
      readOnly: true
  ...
  ...
  volumes:
  - emptyDir: {}
    name: cdr-volume
  - configMap:
      defaultMode: 420
      name: common-config
    name: common-config
  - name: default-token-4dc54
    secret:
      defaultMode: 420
      secretName: default-token-4dc54
status:
  ...
  ...

Removing an Object

We may also use ECD Patch to remove a provisioned K8S object. From mounting a storage example, now we can use the directive marker ( $patch: delete ) to remove the volume and volumeMount.

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Version	Old Version 5	New Version 6
Changes made by	Jacob Almqvist	Jacob Almqvist
Saved on	Sept 16, 2024	Sept 16, 2024

Versions Compared

Key

Samples

Changing Rollout Strategy

Setting Toleration

Setting Environment Variable

Mounting a storage

Removing an Object