Developer Instructions for maintaining the Kubernetes Manifests

This document describes the methods of creating and maintaining Kubernetes manifests in a simpler and easy to user format.

Image Tag Update

In order to update the image tag for a particular component, please edit the corresponding Deployment manifest in cim-solution/kubernetes/cim/Deployments folder and change the image tag to the required value.

CODE

[root@devops230 Deployments]# more ef-reporting-connector-deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    ef.service: ef-reporting-connector
    ef: expertflow
  name: ef-reporting-connector
  namespace: expertflow

spec:
  replicas: 1
  selector:
    matchLabels:
      ef.service: ef-reporting-connector
  template:
    metadata:
      labels:
        ef.service: ef-reporting-connector
        ef: expertflow
    spec:
      imagePullSecrets:
      - name: expertflow-reg-cred
      containers:
        - image: gitlab.expertflow.com:9242/cim/reporting-connector/build:1.2
          name: ef-reporting-connector
          imagePullPolicy: IfNotPresent
          volumeMounts:
            - name: config-volume-conf
              mountPath: /root/config/reporting-connector.conf
              subPath: reporting-connector.conf
            - name: config-volume-cron
              mountPath: /etc/crontabs/root
              subPath: root
      volumes:
         - name: config-volume-conf
           configMap:
             name: ef-reporting-connector-conf
             optional: true
         - name: config-volume-cron
           configMap:
             name: ef-reporting-connector-cron
             items:
               - key: reporting-connector-cron
                 path: root

      restartPolicy: Always

To Apply the changed information, please delete the previous deployment using

CODE

kubectl delete -f Deployments/ef-<component>-deployment.yaml

and the re-apply the manifest using

CODE

kubectl apply -f Deployments/ef-<component>-deployment.yaml

Config-Maps

Config-Maps are meant to provide variable data which must be kept external to the container image like Container Environment and configuration files.

Currently in CIM , we are using 2 different types of Config-Maps

Environment Config-Maps

These are used to configure the Environment variables in key: value format and are then extended to the container process via the config-maps. The container process sees this list as environment variables similar to the way we use in our SHELL using 'export VAR=VAL' command

In order to create the environment based Config-Maps, please follow these steps

In this example we are going to add a variable called NEW_VARIABLES with the value of "true" in component 360-Connector's config-Map with the name of 'ef-connector360-cm'

change path

CODE

cd cim-solution/kubernetes/cim/ConfigMaps

Edit the ConfigMap as per the existing lines like

CODE

apiVersion: v1
data:
  CCM_URL: http://ef-ccm-svc:8081/message/receive
  CONNECT_TIMEOUT: "3000"
  FILE_ENGINE_URL: https://ef-file-engine-svc:8443/
  READ_TIMEOUT: "10000"
  NEW_VARIABLES: "true"
kind: ConfigMap
metadata:
  labels:
    ef.service: 360-connector
    ef: expertflow
  name: ef-connector360-cm
  namespace: expertflow

A new variables with the name of NEW_VARIABLES with the value of "true" has been added.

Now edit the deployment of the same CIM component for which the environment Config-Map has been changed and extend the change to deployment so that container can borrow it.

Go the the Deployments Folder

CODE

cd ../Deployment

Edit the corresponding component's Deployment file

CODE

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    ef.service: ef-360-connector
    ef: expertflow
  name: ef-360-connector
  namespace: expertflow

spec:
  replicas: 1
  selector:
    matchLabels:
      ef.service: ef-360-connector
  template:
    metadata:
      labels:
        ef.service: ef-360-connector
        ef: expertflow
    spec:
      imagePullSecrets:
      - name: expertflow-reg-cred
      containers:
        - env:
             - name: NEW_VARIABLES
              valueFrom:
                configMapKeyRef:
                  key: NEW_VARIABLES
                  name: ef-connector360-cm 
            - name: CCM_URL
              valueFrom:
                configMapKeyRef:
                  key: CCM_URL
                  name: ef-connector360-cm
            - name: CONNECT_TIMEOUT
              valueFrom:
                configMapKeyRef:
                  key: CONNECT_TIMEOUT
                  name: ef-connector360-cm
            - name: FILE_ENGINE_URL
              valueFrom:
                configMapKeyRef:
                  key: FILE_ENGINE_URL
                  name: ef-connector360-cm
            - name: READ_TIMEOUT
              valueFrom:
                configMapKeyRef:
                  key: READ_TIMEOUT
                  name: ef-connector360-cm
          image: gitlab.expertflow.com:9242/cim/360-connector/build:1.0-SR13_f-CIM-6938-1374e672ae6078fa7413aac858bad8fce91b5b48
          name: ef-360-connector
          imagePullPolicy: IfNotPresent
          ports:
           - containerPort: 8080
      restartPolicy: Always

Add the newly added environment Config-Map entry in the Deployment and save the file. The newly added config-map entry will always look like

CODE

              - name: VARIABLE_NAME
              valueFrom:
                configMapKeyRef:
                  key: VARIABLE_NAME
                  name: CONFIG-MAP-NAME

where the VARIABLE_NAME is the variable that we introduced in our first step and the CONFIG-MAP is the name of its config-map edited in first step.

Once the Config-Map has been updated, the corresponding component's POD will have to re-created . Apply the changes by

deleting the existing config-map

CODE

kubectl delete -f ConfigMaps/<name-of-config-map>.yaml

delete the corresponding pod

CODE

kubectl delete -f Deployment/ef-<component>-deployment.yaml

Now apply the new config-map

CODE

kubectl  apply -f ConfigMap/<name-of-config-map>.yaml

and re-create the POD using

CODE

kubectl apply -f Deployment/ef-<component>-deployment.yaml

the newly added variable will be made available to the container process. You can verify this by exec'ing into the the container/POD and issuing the 'env' command on your SHELL prompt.

CODE

kubectl -n expertflow exec -ti <POD-NAME> -- sh

# env

File-System Config-Maps

This method allows us to use the configuration files ( <= 1 MB file per ConfigMap) as file-name:file-contents pairs and then inherit these files in different locations inside the directory structure of the container. These config-maps can be used READ-ONLY mechanism to mount files.

In this example we will be mounting a file "reporting-connector.conf" as config-map to the Reporting-Connector container and then mount this file at "/root/config/reporting-connector.conf" inside the container, so that it is always available to the container as a regular file.

Create the Config-map from the file that we want to add using

CODE

kubectl -n expertflow create configmap <config-map-name> --from-file=reporting-connector.conf

Edit the Deployment of the component in Deployments folder under cim-solution/kubernetes/cim/Deployments

CODE

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    ef.service: ef-reporting-connector
    ef: expertflow
  name: ef-reporting-connector
  namespace: expertflow

spec:
  replicas: 1
  selector:
    matchLabels:
      ef.service: ef-reporting-connector
  template:
    metadata:
      labels:
        ef.service: ef-reporting-connector
        ef: expertflow
    spec:
      imagePullSecrets:
      - name: expertflow-reg-cred
      containers:
        - image: gitlab.expertflow.com:9242/cim/reporting-connector/build:1.2
          name: ef-reporting-connector
          imagePullPolicy: IfNotPresent
          volumeMounts:
            - name: config-volume-conf
              mountPath: /root/config/reporting-connector.conf
              subPath: reporting-connector.conf
            - name: config-volume-cron
              mountPath: /etc/crontabs/root
              subPath: root
      volumes:
         - name: config-volume-conf
           configMap:
             name: ef-reporting-connector-conf
             optional: true
         - name: config-volume-cron
           configMap:
             name: ef-reporting-connector-cron
             items:
               - key: reporting-connector-cron
                 path: root

      restartPolicy: Always

Here are the details how it works.

Initially we added these lines

CODE

           volumeMounts:
            - name: config-volume-conf
              mountPath: /root/config/reporting-connector.conf
              subPath: reporting-connector.conf

This means that there is a volume attachment to the POD/container with the name of config-volume-conf and its contents should be fetched from the volume name config-volume-conf .

The volume now points to the actual config-map using

CODE

       volumes:
         - name: config-volume-conf
           configMap:
             name: ef-reporting-connector-conf
             optional: true

The Volume Definition now explains that the volume contents are to be fetched from the configmap called ef-reporting-connector-conf . Once these conditions are met, the config is inheritied to the container as a file to be mounted on /root/config/reporting-connector.conf path.

A similar approach will needed to delete both Config-Map and running POD for the information to be transferred to the Container.