k8s_basic_deployments

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k8s_basic_deployments [2020/05/02 16:05] – andonovjk8s_basic_deployments [2020/05/03 12:16] (current) – andonovj
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-{{ :deploymentoverview.jpg?500 |}}+{{:deploymentoverview.jpg?500|}}
  
  
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 Again, we can check if our app is working: Again, we can check if our app is working:
  
-{{ :deploymenttest.jpg?400 |}}+{{:deploymenttest.jpg?400|}} 
 + 
 + 
 +====Replica Sets==== 
 +As already mentioned, deployments operate with Replicat Sets, NOT replication Controllers. Eventhough that is a new objects, it inherits a lot of stuff from the replication controller. You can check the Replica sets, almost the same as the replication controller and notice that we don't have Replication Controllers anymore...after I have deleted them in the past of course. 
 + 
 +<Code: bash|Check Replica Sets> 
 +ubuntu@k8s-master:~$ kubectl get rs 
 +NAME                     DESIRED   CURRENT   READY   AGE 
 +hello-deploy-6cd458494   10        10        10      11m 
 +ubuntu@k8s-master:~$ kubectl get rc 
 +No resources found in default namespace. 
 +ubuntu@k8s-master:~$ kubectl describe rs 
 +Name:           hello-deploy-6cd458494 
 +Namespace:      default 
 +Selector:       app=hello-date,pod-template-hash=6cd458494 
 +Labels:         app=hello-date 
 +                pod-template-hash=6cd458494 
 +Annotations:    deployment.kubernetes.io/desired-replicas: 10 
 +                deployment.kubernetes.io/max-replicas: 13 
 +                deployment.kubernetes.io/revision: 1 
 +Controlled By:  Deployment/hello-deploy 
 +Replicas:       10 current / 10 desired 
 +Pods Status:    10 Running / 0 Waiting / 0 Succeeded / 0 Failed 
 +Pod Template: 
 +  Labels:  app=hello-date 
 +           pod-template-hash=6cd458494 
 +  Containers: 
 +   hello-pod: 
 +    Image:        andonovj/httpserverdemo:latest 
 +    Port:         1234/TCP 
 +    Host Port:    0/TCP 
 +    Environment:  <none> 
 +    Mounts:       <none> 
 +  Volumes:        <none> 
 +Events: 
 +  Type    Reason            Age   From                   Message 
 +  ----    ------            ----  ----                   ------- 
 +  Normal  SuccessfulCreate  16m   replicaset-controller  Created pod: hello-deploy-6cd458494-mjtw9 
 +  Normal  SuccessfulCreate  16m   replicaset-controller  Created pod: hello-deploy-6cd458494-m9bgx 
 +  Normal  SuccessfulCreate  16m   replicaset-controller  Created pod: hello-deploy-6cd458494-44jvs 
 +  Normal  SuccessfulCreate  16m   replicaset-controller  Created pod: hello-deploy-6cd458494-6v8lt 
 +  Normal  SuccessfulCreate  16m   replicaset-controller  Created pod: hello-deploy-6cd458494-zwh4l 
 +  Normal  SuccessfulCreate  16m   replicaset-controller  Created pod: hello-deploy-6cd458494-jf594 
 +  Normal  SuccessfulCreate  16m   replicaset-controller  Created pod: hello-deploy-6cd458494-vd7mt 
 +  Normal  SuccessfulCreate  16m   replicaset-controller  Created pod: hello-deploy-6cd458494-nq2wx 
 +  Normal  SuccessfulCreate  16m   replicaset-controller  Created pod: hello-deploy-6cd458494-f8j5f 
 +  Normal  SuccessfulCreate  16m   replicaset-controller  (combined from similar events): Created pod: hello-deploy-6cd458494-dxqh7 
 +  
 +ubuntu@k8s-master:~$ kubectl get rc 
 +No resources found in default namespace.                     <- We don't have Replication Controllers anymore. 
 +</Code> 
 + 
 +=====Rolling-Updates===== 
 +Now, we have deployed application, which is totally scalable and redundancy is provided as Hell :) But what if want to fix couple bugs, or present new version.  
 + 
 +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 
 +{ 
 +    using System; 
 +    using System.Net; 
 +    using System.Net.Sockets; 
 +    using System.Text; 
 +    using System.Threading.Tasks; 
 +    using System.IO; 
 +    using System.Threading; 
 +    class Program 
 +    { 
 +        public async static Task Main(string[] args) 
 +        { 
 +            TcpListener tcpListener = new TcpListener(IPAddress.Any, 1234); 
 +            tcpListener.Start(); 
 +            while (true) 
 +            { 
 +                TcpClient tcpClient = await tcpListener.AcceptTcpClientAsync(); 
 +                await ProcessClientAsync(tcpClient); 
 +            } 
 +        } 
 + 
 +        public static async Task ProcessClientAsync(TcpClient tcpClient) 
 +        { 
 +            const string NewLine = "\r\n"; 
 +            using (var networkStream = tcpClient.GetStream()) 
 +            { 
 +                byte[] requestBytes = new byte[1000000];   //TODO USE Buffer 
 +                int bytesRead = await networkStream.ReadAsync(requestBytes, 0, requestBytes.Length); 
 +                string request = Encoding.UTF8.GetString(requestBytes, 0, bytesRead); 
 +                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 
 +                                 + "Server: SoftuniServer/1.0 " + NewLine 
 +                                 + "Content-Type: text/html" + NewLine 
 +                                 + "Content-Length: " + responseText.Length + NewLine + NewLine 
 +                                 + responseText; 
 + 
 +                byte[] responseBytes = Encoding.UTF8.GetBytes(response); 
 +                await networkStream.WriteAsync(responseBytes, 0, responseBytes.Length); 
 +                Console.WriteLine(request); 
 +                Console.WriteLine(new string('=', 60)); 
 +            } 
 +        } 
 +    } 
 +} 
 +</Code> 
 + 
 +You see that "v2" after "Working", yes, I just added it now. Let's rebuild via docker, upload it and edit our edition to v2 :) 
 +The Rebuild part you can see in the Docker section, but I will put the output here as well: 
 + 
 +====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 
 +1         <none> 
 +2         <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 
 +3         <none> 
 +4         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.
  • k8s_basic_deployments.1588435544.txt.gz
  • Last modified: 2020/05/02 16:05
  • by andonovj