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--- k8s_basic_deployments [2020/05/02 16:33] – andonovj
+++ k8s_basic_deployments [2020/05/03 12:16] (current) – andonovj
@@ Line 153: / Line 153: @@
 What we do then ?
 Well, let's edit our application, let's add "v2" into our awesome app:
+====Edit Software====
 <Code: C#|Edit Source>
 namespace HttpServerDemo
@@ Line 166: / Line 166: @@
     using System.IO;
     using System.Threading;
     class Program
     {
@@ Line 173: / Line 172: @@
             TcpListener tcpListener = new TcpListener(IPAddress.Any, 1234);
             tcpListener.Start();
             while (true)
             {
                 TcpClient tcpClient = await tcpListener.AcceptTcpClientAsync();
                 await ProcessClientAsync(tcpClient);
             }
         }
@@ Line 190: / Line 187: @@
                 int bytesRead = await networkStream.ReadAsync(requestBytes, 0, requestBytes.Length);
                 string request = Encoding.UTF8.GetString(requestBytes, 0, bytesRead);
-                string responseText = @"<h1>Working... v2</h1>" +
+                string responseText = @"<h1>Working... v2</h1>" +                      <- Updated this line with "v2" :)
                                           $"<form> <h1> Time is: {System.DateTime.Now} </h1> </form>";
                 string response = "HTTP/1.1 200 OK" + NewLine
@@ Line 211: / Line 208: @@
 The Rebuild part you can see in the Docker section, but I will put the output here as well:
-<Code: bash|Update our software>
+====Dockerize, Tag & Push===
+<Code: bash|Dockerize, Tag & Push>
+[root@postgresqlmaster httpserverdemo]# ls -lart
+total 16
+-rw-r--r--. 1 root root  178 Jan 15 11:29 HttpServerDemo.csproj
+-rw-r--r--. 1 root root  405 Jan 24 07:20 Dockerfile
+-rw-r--r--. 1 root root 1904 May  2 12:19 Program.cs
+dr-xr-x---. 7 root root 4096 May  2 12:39 ..
+drwxr-xr-x. 2 root root   71 May  2 12:45 .
+root@k8s-master:/home/vagrant/HttpServerDemo# docker build -t httpserverdemo .
+Sending build context to Docker daemon  6.144kB
+Step 1/11 : FROM mcr.microsoft.com/dotnet/core/sdk:3.1 AS build-env
+ ---> 4aa6a74611ff
+Step 2/11 : WORKDIR /app
+ ---> Using cache
+ ---> e6fb8470c359
+Step 3/11 : COPY *.csproj ./
+ ---> Using cache
+ ---> c6e7e3257ccd
+Step 4/11 : RUN dotnet restore
+ ---> Using cache
+ ---> 073b0e6dcfac
+Step 5/11 : COPY . ./
+ ---> dbb416239305
+Step 6/11 : RUN dotnet publish -c Release -o out
+ ---> Running in cdccacf739ec
+Microsoft (R) Build Engine version 16.5.0+d4cbfca49 for .NET Core
+Copyright (C) Microsoft Corporation. All rights reserved.
+  Restore completed in 38.37 ms for /app/HttpServerDemo.csproj.
+  HttpServerDemo -> /app/bin/Release/netcoreapp3.1/HttpServerDemo.dll
+  HttpServerDemo -> /app/out/
+Removing intermediate container cdccacf739ec
+ ---> 29d5a30972d4
+Step 7/11 : FROM mcr.microsoft.com/dotnet/core/sdk:3.1
+ ---> 4aa6a74611ff
+Step 8/11 : WORKDIR /app
+ ---> Using cache
+ ---> e6fb8470c359
+Step 9/11 : COPY --from=build-env /app/out .
+ ---> ff034e158a2e
+Step 10/11 : RUN find -type d -name bin -prune -exec rm -rf {} \; && find -type d -name obj -prune -exec rm -rf {} \;
+ ---> Running in e217c60056a6
+Removing intermediate container e217c60056a6
+ ---> f3755f21e57e
+Step 11/11 : ENTRYPOINT ["dotnet", "HttpServerDemo.dll"]
+ ---> Running in e49283dde769
+Removing intermediate container e49283dde769
+ ---> 9f2f48860257
+Successfully built 9f2f48860257
+</Code>
+aaaaand....we are done :) We have edited our awesome software and uploaded it to docker hub.
+Let's now update the containers in the pods :)
+====Perform the Update====
+For that purpose, we have to edit the YAML file with couple more values like:
+  * Strategy: RollingUpdate(default)
+  * maxUnavailable: 1 - Never have more than 1 unavailable
+  * maxSurge: 1 - Never have more than 1 additional. In our case, never have more than 11 pods
+So, our YAML file should look as follows:
+<Code: bash| Updated YAML file>
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: hello-deploy
+spec:
+  replicas: 10
+  minReadySeconds: 10
+  strategy:
+    type: RollingUpdate
+    rollingUpdate:
+      maxUnavailable: 1
+      maxSurge: 1
+  selector:
+    matchLabels:
+      app: hello-date
+  template:
+    metadata:
+      labels:
+        app: hello-date
+    spec:
+      containers:
+      - name: hello-pod
+        image: andonovj/httpserverdemo:v2
+        ports:
+        - containerPort: 1234
 </Code>
+Once we have the file, you can start the process as so:
+<Code: bash|Rolling Update Status>
+ubuntu@k8s-master:~$ kubectl apply -f deploy.yml
+Warning: kubectl apply should be used on resource created by either kubectl create --save-config or kubectl apply
+deployment.apps/hello-deploy configured
+</Code>
+You can see the progress of the Rolling Update as follows:
+<Code: bash|Rolling Update Status>
+ubuntu@k8s-master:~$ kubectl rollout status deploy hello-deploy
+Waiting for deployment "hello-deploy" rollout to finish: 2 out of 10 new replicas have been updated...
+^Cubuntu@k8s-master:~$ kubectl get pods
+NAME                            READY   STATUS              RESTARTS   AGE
+hello-deploy-6cd458494-6mvt7    1/1     Running             0          80s
+hello-deploy-6cd458494-9bl7c    1/1     Running             0          80s
+hello-deploy-6cd458494-fvwvz    1/1     Running             0          80s
+hello-deploy-6cd458494-grp2w    1/1     Running             0          80s
+hello-deploy-6cd458494-ldsxq    1/1     Running             0          80s
+hello-deploy-6cd458494-lpgdj    1/1     Running             0          80s
+hello-deploy-6cd458494-mjsmh    1/1     Running             0          80s
+hello-deploy-6cd458494-rd58j    1/1     Running             0          80s
+hello-deploy-6cd458494-rrkhq    1/1     Running             0          80s
+hello-deploy-7f44bd8b96-k92sr   0/1     ContainerCreating   0          23s
+hello-deploy-7f44bd8b96-lqmdx   0/1     ContainerCreating   0          23s
+ubuntu@k8s-master:~$ kubectl rollout status deploy hello-deploy
+Waiting for deployment "hello-deploy" rollout to finish: 4 out of 10 new replicas have been updated...
+Waiting for deployment "hello-deploy" rollout to finish: 4 out of 10 new replicas have been updated...
+Waiting for deployment "hello-deploy" rollout to finish: 6 out of 10 new replicas have been updated...
+Waiting for deployment "hello-deploy" rollout to finish: 6 out of 10 new replicas have been updated...
+Waiting for deployment "hello-deploy" rollout to finish: 6 out of 10 new replicas have been updated...
+Waiting for deployment "hello-deploy" rollout to finish: 6 out of 10 new replicas have been updated...
+Waiting for deployment "hello-deploy" rollout to finish: 6 out of 10 new replicas have been updated...
+Waiting for deployment "hello-deploy" rollout to finish: 8 out of 10 new replicas have been updated...
+Waiting for deployment "hello-deploy" rollout to finish: 8 out of 10 new replicas have been updated...
+Waiting for deployment "hello-deploy" rollout to finish: 8 out of 10 new replicas have been updated...
+Waiting for deployment "hello-deploy" rollout to finish: 8 out of 10 new replicas have been updated...
+Waiting for deployment "hello-deploy" rollout to finish: 8 out of 10 new replicas have been updated...
+Waiting for deployment "hello-deploy" rollout to finish: 1 old replicas are pending termination...
+Waiting for deployment "hello-deploy" rollout to finish: 1 old replicas are pending termination...
+Waiting for deployment "hello-deploy" rollout to finish: 1 old replicas are pending termination...
+Waiting for deployment "hello-deploy" rollout to finish: 1 old replicas are pending termination...
+</Code>
+We can also check the version which is currently being used:
+<Code: bash|Rolling Update Status>
+ubuntu@k8s-master:~$ kubectl get deploy hello-deploy
+NAME           READY   UP-TO-DATE   AVAILABLE   AGE
+hello-deploy   10/10   10           10          5m7s
+ubuntu@k8s-master:~$ kubectl describe deploy hello-deploy
+Name:                   hello-deploy
+Namespace:              default
+CreationTimestamp:      Sun, 03 May 2020 11:28:33 +0000
+Labels:                 <none>
+Annotations:            deployment.kubernetes.io/revision: 2
+Selector:               app=hello-date
+Replicas:               10 desired | 10 updated | 10 total | 10 available | 0 unavailable
+StrategyType:           RollingUpdate
+MinReadySeconds:        10
+RollingUpdateStrategy:  1 max unavailable, 1 max surge
+Pod Template:
+  Labels:  app=hello-date
+  Containers:
+   hello-pod:
+    Image:        andonovj/httpserverdemo:edge                        <- We are using the "edge" version, which we have just compiled.
+    Port:         1234/TCP
+    Host Port:    0/TCP
+    Environment:  <none>
+    Mounts:       <none>
+  Volumes:        <none>
+Conditions:
+  Type           Status  Reason
+  ----           ------  ------
+  Available      True    MinimumReplicasAvailable
+  Progressing    True    NewReplicaSetAvailable
+OldReplicaSets:  <none>
+NewReplicaSet:   hello-deploy-7f44bd8b96 (10/10 replicas created)
+Events:
+  Type    Reason             Age                 From                   Message
+  ----    ------             ----                ----                   -------
+  Normal  ScalingReplicaSet  5m11s               deployment-controller  Scaled up replica set hello-deploy-6cd458494 to 10
+  Normal  ScalingReplicaSet  4m14s               deployment-controller  Scaled up replica set hello-deploy-7f44bd8b96 to 1
+  Normal  ScalingReplicaSet  4m14s               deployment-controller  Scaled down replica set hello-deploy-6cd458494 to 9
+  Normal  ScalingReplicaSet  4m14s               deployment-controller  Scaled up replica set hello-deploy-7f44bd8b96 to 2
+  Normal  ScalingReplicaSet  2m18s               deployment-controller  Scaled down replica set hello-deploy-6cd458494 to 7
+  Normal  ScalingReplicaSet  2m18s               deployment-controller  Scaled up replica set hello-deploy-7f44bd8b96 to 4
+  Normal  ScalingReplicaSet  2m3s                deployment-controller  Scaled down replica set hello-deploy-6cd458494 to 5
+  Normal  ScalingReplicaSet  2m3s                deployment-controller  Scaled up replica set hello-deploy-7f44bd8b96 to 6
+  Normal  ScalingReplicaSet  108s                deployment-controller  Scaled down replica set hello-deploy-6cd458494 to 3
+  Normal  ScalingReplicaSet  82s (x4 over 108s)  deployment-controller  (combined from similar events): Scaled down replica set hello-deploy-6cd458494 to 0
+</Code>
+=====Rolling Back=====
+Now, before we continue, let's speak a little bit about Change History. We can check the history of all changes as follows:
+<Code: bash| Check Change History>
+ubuntu@k8s-master:~$ kubectl rollout history deploy hello-deploy
+deployment.apps/hello-deploy
+REVISION  CHANGE-CAUSE
+         <none>
+         <none>
+</Code>
+The reason why you don't see anything in the "change-cause" is because we didn't use "-record" when we applied the change. But let's reverse our changes and apply them again. We can reverse our changes using the following command:
+<Code: bash| Rollback>
+ubuntu@k8s-master:~$ kubectl rollout undo deployment hello-deploy --to-revision=1
+deployment.apps/hello-deploy rolled back
+ubuntu@k8s-master:~$
+</Code>
+Of course we can monitor it with the same command as before:
+<Code: bash| Rollback>
+ubuntu@k8s-master:~$ kubectl rollout status deploy hello-deploy
+Waiting for deployment "hello-deploy" rollout to finish: 4 out of 10 new replicas have been updated...
+Waiting for deployment "hello-deploy" rollout to finish: 4 out of 10 new replicas have been updated...
+Waiting for deployment "hello-deploy" rollout to finish: 6 out of 10 new replicas have been updated...
+Waiting for deployment "hello-deploy" rollout to finish: 6 out of 10 new replicas have been updated...
+Waiting for deployment "hello-deploy" rollout to finish: 6 out of 10 new replicas have been updated...
+Waiting for deployment "hello-deploy" rollout to finish: 6 out of 10 new replicas have been updated...
+Waiting for deployment "hello-deploy" rollout to finish: 6 out of 10 new replicas have been updated...
+Waiting for deployment "hello-deploy" rollout to finish: 8 out of 10 new replicas have been updated...
+Waiting for deployment "hello-deploy" rollout to finish: 8 out of 10 new replicas have been updated...
+Waiting for deployment "hello-deploy" rollout to finish: 8 out of 10 new replicas have been updated...
+Waiting for deployment "hello-deploy" rollout to finish: 8 out of 10 new replicas have been updated...
+Waiting for deployment "hello-deploy" rollout to finish: 8 out of 10 new replicas have been updated...
+Waiting for deployment "hello-deploy" rollout to finish: 1 old replicas are pending termination...
+Waiting for deployment "hello-deploy" rollout to finish: 1 old replicas are pending termination...
+Waiting for deployment "hello-deploy" rollout to finish: 1 old replicas are pending termination...
+Waiting for deployment "hello-deploy" rollout to finish: 1 old replicas are pending termination...
+deployment "hello-deploy" successfully rolled out
+ubuntu@k8s-master:~$ kubectl describe deploy
+Name:                   hello-deploy
+Namespace:              default
+CreationTimestamp:      Sun, 03 May 2020 11:28:33 +0000
+Labels:                 <none>
+Annotations:            deployment.kubernetes.io/revision: 3
+Selector:               app=hello-date
+Replicas:               10 desired | 10 updated | 10 total | 10 available | 0 unavailable
+StrategyType:           RollingUpdate
+MinReadySeconds:        10
+RollingUpdateStrategy:  1 max unavailable, 1 max surge
+Pod Template:
+  Labels:  app=hello-date
+  Containers:
+   hello-pod:
+    Image:        andonovj/httpserverdemo:latest             <- We are back to the old deployment.
+    Port:         1234/TCP
+    Host Port:    0/TCP
+    Environment:  <none>
+    Mounts:       <none>
+  Volumes:        <none>
+Conditions:
+  Type           Status  Reason
+  ----           ------  ------
+  Available      True    MinimumReplicasAvailable
+  Progressing    True    NewReplicaSetAvailable
+OldReplicaSets:  <none>
+NewReplicaSet:   hello-deploy-6cd458494 (10/10 replicas created)
+Events:
+  Type    Reason             Age                From                   Message
+  ----    ------             ----               ----                   -------
+  Normal  ScalingReplicaSet  45m                deployment-controller  Scaled up replica set hello-deploy-6cd458494 to 10
+  Normal  ScalingReplicaSet  44m                deployment-controller  Scaled up replica set hello-deploy-7f44bd8b96 to 1
+  Normal  ScalingReplicaSet  44m                deployment-controller  Scaled down replica set hello-deploy-6cd458494 to 9
+</Code>
+====Rollupdate with Record====
+Let's again apply the RollUpdate WITH the record this time:
+<Code: bash|Rollupdate with Record>
+ubuntu@k8s-master:~$ kubectl apply -f deploy.yml --record
+deployment.apps/hello-deploy configured
+ubuntu@k8s-master:~$
+ubuntu@k8s-master:~$ kubectl rollout history deploy hello-deploy
+deployment.apps/hello-deploy
+REVISION  CHANGE-CAUSE
+         <none>
+         kubectl apply --filename=deploy.yml --record=true
+</Code>
+Now, we can see that, the record is there and we can see the history of changes.