k8s_basic_deployments

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k8s_basic_deployments [2020/05/02 16:08] – andonovjk8s_basic_deployments [2020/05/03 12:16] (current) – andonovj
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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|}}
  
  
Line 108: Line 108:
 ubuntu@k8s-master:~$ kubectl get rc ubuntu@k8s-master:~$ kubectl get rc
 No resources found in default namespace. 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:~$ ubuntu@k8s-master:~$
 </Code> </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.1588435731.txt.gz
  • Last modified: 2020/05/02 16:08
  • by andonovj