Red Hat OpenShift Administration II: Configuring a Production Cluster
Deploy and update an application from resource manifests from YAML files that are stored in a Git server.
Outcomes
Deploy applications from resource manifests from YAML files that are stored in a GitLab repository.
Inspect new manifests for potential update issues.
Update application deployments from new YAML manifests.
Force the redeployment of pods when necessary.
As the student user on the workstation machine, use the lab command to prepare your system for this exercise.
[student@workstation ~]$ lab start declarative-manifests
Instructions
Log in to the OpenShift cluster and create the
declarative-manifestsproject.Log in to the cluster as the
developeruser.[student@workstation ~]$
oc login -u developer -p developer \ https://api.ocp4.example.com:6443Login successful. ...output omitted...Create the
declarative-manifestsproject.[student@workstation ~]$
oc new-project declarative-manifestsNow using project "declarative-manifests" on server ... ...output omitted...
Clone the
declarative-manifestproject from the Git repository.Change your directory to the project
labsdirectory.[student@workstation ~]$
cd ~/DO280/labsClone the Git repository from
https://git.ocp4.example.com/developer/declarative-manifests.git. Usedeveloperfor both the username and for the password.[student@workstation lab]$
git clone \ https://git.ocp4.example.com/developer/declarative-manifests.gitCloning into 'declarative-manifests'... remote: Enumerating objects: 24, done. remote: Counting objects: 100% (24/24), done. remote: Compressing objects: 100% (21/21), done. remote: Total 24 (delta 8), reused 0 (delta 0), pack-reused 0 Receiving objects: 100% (24/24), done. Resolving deltas: 100% (8/8), done.Go to the
declarative-manifestdirectory.[student@workstation lab]$
cd declarative-manifests[student@workstation declarative-manifests]$
Inspect the contents of the Git repository.
List the contents of the
declarative-manifestsdirectory.[student@workstation declarative-manifests]$
ls -lAtotal 12 -rw-rw-r--. 1 student student 3443 Jun 21 16:39 database.yaml -rw-rw-r--. 1 student student 2278 Jun 21 16:39 exoplanets.yaml drwxrwxr-x. 8 student student 163 Jun 21 16:39 .git -rw-rw-r--. 1 student student 0 Jun 21 16:39 .gitkeep -rw-rw-r--. 1 student student 11 Jun 21 16:39 README.mdList the commits, branches, and tags on the Git repository.
[student@workstation declarative-manifests]$
git log --oneline4045336 (HEAD -> main, tag:third, origin/v1.1.1, origin/main, origin/HEAD) Exoplanets v1.1.1
ad455b2 Database v1.1.1
821420c (tag: second, origin/v1.1.0) Exoplanets v1.1.0
d9abeb0 (tag: first, origin/v1.0) Exoplanets v1.0
a11396e Database v1.0
e868a90 README
18ddf3c Initial commit The
v1.1.1branch points to the third version of the application. The
v1.1.0branch points to the second version of the application. The
v1.0branch points to the first version of the application.
Deploy the resource manifests of the first application version.
Switch to the
v1.0branch, which contains the YAML manifests for the first version of the application.[student@workstation declarative-manifests]$
git checkout v1.0branch 'v1.0' set up to track 'origin/v1.0'. Switched to a new branch 'v1.0'Validate the YAML resource manifest for the application.
[student@workstation declarative-manifests]$
oc apply -f . \ --validate=true --dry-run=serverconfigmap/database created (server dry run) secret/database created (server dry run) deployment.apps/database created (server dry run) service/database created (server dry run) configmap/exoplanets created (server dry run) secret/exoplanets created (server dry run) deployment.apps/exoplanets created (server dry run) service/exoplanets created (server dry run) route.route.openshift.io/exoplanets created (server dry run)Deploy the exoplanets application.
[student@workstation declarative-manifests]$
oc apply -f .configmap/database created secret/database created deployment.apps/database created service/database created configmap/exoplanets created secret/exoplanets created deployment.apps/exoplanets created service/exoplanets created route.route.openshift.io/exoplanets createdList the deployments and pods. The exoplanets pod can go into a temporary crash loop backoff state if it attempts to access the database before it becomes available. Wait for the pods to be ready. Press Ctrl+C to exit the
watchcommand.[student@workstation declarative-manifests]$
watch oc get deployments,podsEvery 2.0s: oc get deployments,pods ... NAMEREADYUP-TO-DATE AVAILABLE AGE deployment.apps/database1/11 1 32s deployment.apps/exoplanets1/11 1 32s NAMEREADYSTATUS RESTARTS AGE pod/database-6fddbbf94f-2pghj1/1Running 0 32s pod/exoplanets-64c87f5796-bw8tm1/1Running 0 32sList the route for the exoplanets application.
[student@workstation declarative-manifests]$
oc get routes -l app=exoplanetsNAME HOST/PORT ... exoplanetsexoplanets-declarative-manifests.apps.ocp4.example.com...Open the route URL in the web browser. The application version is
v1.0.http://exoplanets-declarative-manifests.apps.ocp4.example.com/
Deploy the second version of the exoplanets application.
Switch to the
v1.1.0branch of the Git repository.[student@workstation declarative-manifests]$
git checkout v1.1.0branch 'v1.1.0' set up to track 'origin/v1.1.0'. Switched to a new branch 'v1.1.0'Inspect the changes from the new manifests.
[student@workstation declarative-manifests]$
oc diff -f ....output omitted... - secretRef: name: exoplanets - image: registry.ocp4.example.com:8443/redhattraining/exoplanets:v1.0 + image: registry.ocp4.example.com:8443/redhattraining/exoplanets:v1.1.0 imagePullPolicy: Always livenessProbe: failureThreshold: 3The new version changes the image that is deployed to the cluster. Because the change is in the deployment, the new manifest produces new pods for the application.
Apply the changes from the new manifests.
[student@workstation declarative-manifests]$
oc apply -f .configmap/database unchanged secret/database configured deployment.apps/database configured service/database configured configmap/exoplanets unchanged secret/exoplanets configured deployment.apps/exoplanets configured service/exoplanets unchanged route.route.openshift.io/exoplanets configuredList the deployments and pods. Wait for the application pod to be ready. Press Ctrl+C to exit the
watchcommand.[student@workstation declarative-manifests]$
watch oc get deployments,podsEvery 2.0s: oc get deployments,pods ... NAME READY UP-TO-DATE AVAILABLE AGE deployment.apps/database 1/1 1 1 6m32s deployment.apps/exoplanets 1/1 1 1 6m33s NAMEREADYSTATUS RESTARTS AGE pod/database-6fddbbf94f-2pghj 1/1 Running 0 6m33s pod/exoplanets-74c85f5796-tw8tf1/1Running 0 32sList the route for the exoplanets application.
[student@workstation declarative-manifests]$
oc get routes -l app=exoplanetsNAME HOST/PORT ... exoplanetsexoplanets-declarative-manifests.apps.ocp4.example.com...Open the route URL in the web browser. The application version is
v1.1.0.http://exoplanets-declarative-manifests.apps.ocp4.example.com/
Deploy the third version of the exoplanets application.
Switch to the
v1.1.1branch of the Git repository.[student@workstation declarative-manifests]$
git checkout v1.1.1branch 'v1.1.1' set up to track 'origin/v1.1.1'. Switched to a new branch 'v1.1.1'View the differences between the currently deployed version of the application and the updated resource manifests.
[student@workstation declarative-manifests]$
oc diff -f ....output omitted... kind: Secret
metadata:
annotations:
...output omitted... - DB_USER: '*** (before)'
+ DB_USER: '*** (after)'
kind: Secret
metadata:
annotations: The secret resource is changed.
The
DB_USERfield of the secret resource is changed.Inspect the current application pods.
[student@workstation declarative-manifests]$
oc get podsNAME READY STATUS RESTARTS AGE database-6fddbbf94f-brlj6 1/1 Running 0 44m exoplanets-674cc57b5d-mv8kd 1/1 Running 0 18mDeploy the new version of the application.
[student@workstation declarative-manifests]$
oc apply -f .configmap/database unchanged secret/database configured deployment.apps/database configured service/database configured configmap/exoplanets unchanged secret/exoplanets configured deployment.apps/exoplanets unchanged service/exoplanets unchanged route.route.openshift.io/exoplanets configuredInspect the current application pods again
[student@workstation declarative-manifests]$
oc get podsNAME READY STATUS RESTARTS AGE database-6fddbbf94f-brlj6 1/1 Running 0 10m exoplanets-674cc57b5d-mv8kd 0/1 CrashLoopBackOff 4 (14s ago) 2mAlthough the secret is updated, the deployed application pods are not changed. These non-updated pods are a problem, because the pods load secrets and configuration maps at startup. Currently, the pods have stale values from the previous configuration, and therefore could crash.
Force the exoplanets application to restart, to flush out any stale configuration data.
Use the
oc get deploymentscommand to confirm the deployments.[student@workstation declarative-manifests]$
oc get deploymentsNAME READY UP-TO-DATE AVAILABLE AGE database 1/1 1 1 32m exoplanets 0/1 1 0 32mUse the
oc rolloutcommand to restart the database deployment.[student@workstation declarative-manifests]$
oc rollout restart \ deployment/databasedeployment.apps/database restartedUse the
oc rolloutcommand to restart the exoplanets deployment.[student@workstation declarative-manifests]$
oc rollout restart \ deployment/exoplanetsdeployment.apps/exoplanets restartedList the pods. The exoplanets pod can go into a temporary crash loop backoff state if it attempts to access the database before it becomes available. Wait for the application pod to be ready. Press Ctrl+C to exit the
watchcommand.[student@workstation declarative-manifests]$
watch oc get podsEvery 2.0s: oc get deployments,pods ... NAME READY STATUS RESTARTS AGEE database-7c767c4bd7-m72nk 1/1 Running 0 32s exoplanets-64c87f5796-bw8tm 1/1 Running 0 32sUse the
oc get deploymentcommand with the-o yamloption to view thelast-applied-configurationannotation.[student@workstation declarative-manifests]$
oc get deployment \ exoplanets -o yamlapiVersion: apps/v1 kind: Deployment metadata: annotations: deployment.kubernetes.io/revision: "3" description: Defines how to deploy the application server kubectl.kubernetes.io/last-applied-configuration: | {"apiVersion":"apps/v1","kind":"Deployment","metadata":{"annotations":... template.alpha.openshift.io/wait-for-ready: "true" ...output omitted...Open the route URL in the web browser. The application version is
v1.1.1.http://exoplanets-declarative-manifests.apps.ocp4.example.com/
Clean up the resources.
Delete the application resources.
[student@workstation declarative-manifests]$
oc delete -f .configmap "database" deleted secret "database" deleted deployment.apps "database" deleted service "database" deleted configmap "exoplanets" deleted secret "exoplanets" deleted deployment.apps "exoplanets" deleted service "exoplanets" deleted route.route.openshift.io "exoplanets" deletedChange to the student HOME directory.
[student@workstation declarative-manifests]$
cd[student@workstation ~]
Red Hat OpenShift Administration II: Operating a Production Kubernetes Cluster (DO280)
Haley_Ruccio
26 lip 2023
Configure, manage, and troubleshoot OpenShift clusters and containerized applicationsRed Hat OpenShift Administration II: Operating a Production Kubernetes Cluster (DO280) prepares OpenShift Cluster Administrators to perform daily administration tasks on clusters that host applications provided by internal teams and external vendors, enable self-service for cluster users with different roles, and deploy applications that require special permissions such as such as CI/CD tooling, performance monitoring, and security scanners. This course focuses on configuring multi-tenancy and security features of OpenShift as well as managing OpenShift add-ons based on operators.The skills you learn in this course can be applied using all versions of OpenShift, including Red Hat OpenShift on AWS (ROSA), Azure Red Hat OpenShift, and OpenShift Container Platform.This course is based on OpenShift Container Platform 4.12.5-10 Course TopicsDeploying packaged applications using manifests, templates, kustomize, and helm.Configuring authentication and authorization for users and applications.Protecting network traffic with network policies and exposing applications with proper network access.Deploying and managing applications using resources manifests.Enabling developer self-service of application projects.Managing OpenShift cluster updates and Kubernetes operator updates.Target AudienceSystem Administrators and Platform Operators interested in the ongoing management of OpenShift clusters, applications, users, and add-ons.Site Reliability Engineers interested in the ongoing maintenance and troubleshooting of Kubernetes clusters.System and Software Architects interested in understanding the security of an OpenShift cluster.Recommended TrainingTake our free assessment to gauge whether this offering is the best fit for your skills.Prerequisite: Red Hat OpenShift I: Containers & Kubernetes (DO180 v4.12), or equivalent skills deploying and managing Kubernetes applications using the OpenShift web console and command-line interfaces.Technology considerationsThis course requires internet access to access the cloud-based classroom environment that provides an OpenShift cluster and a remote administrator’s workstation.
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About pod security standards and warnings
alexcorcoles
17 kwi 2023
(This material has been created with the inputs of instructors and other people. We are trying to get this material published as soon as possible to address some concerns with DO180 and DO280.)With the default configuration, any namespace that you create on OpenShift 4.12 has the following labels: pod-security.kubernetes.io/audit: restrictedpod-security.kubernetes.io/audit-version: v1.24pod-security.kubernetes.io/warn: restrictedpod-security.kubernetes.io/warn-version: v1.24 These labels activate auditing and warning of the restricted pod security standard. The Kubernetes documentation describes the restricted pod security standard. Pod security standards such as restricted are not directly related to security context constraints such as the restricted SCC.Kubernetes uses an admission controller to reject pods that do not comply with pod security standards. An admission controller is a Kubernetes component that inspects every Kubernetes resource before its creation, and acts before Kubernetes creates the resource. This action can include rejecting the creation of the resource, or modifying the resource.The pod security standards are policies that include properties that workloads must follow. For example, the restricted standard requires that containers set the securityContext.allowPrivilegeEscalation field to false.Pod security standards apply both to workloads, such as deployments and jobs, and to pods.When a pod is created, the admission controller inspects the container specifications and enumerates the fields that violate the pod security standard of the namespace. The admission controller inspects the pod-security labels in the namespace to decide which pod security standard to apply (restricted, baseline, or privileged), and which action to take on violations. Namespaces can audit, warn, or enforce pod security standard violations. When the pod-security.kubernetes.io/audit annotation is set to restricted, the admission controller prevents the creation of pods that violate the security standard. When the pod-security.kubernetes.io/audit and pod-security.kubernetes.io/warn annotations are defined in the project, the admission controller does not block the creation of pods, but registers audit events or warnings.The admission controller does not enforce pod security standards for workloads. If the namespace is configured to enforce a pod security standard, then you can create a violating workload. The admission controller enforces only pod security policies on pods.Cluster administrators can use pod security standards to ensure that pods and workloads in namespaces limit their privileges. By limiting privileges, cluster administrators can mitigate what malicious pods can do.The default configuration of user namespaces in OpenShift does not restrict any workload; it only notifies users when they create workloads that do not follow pod security standards that might be enforced in future OpenShift versions.Security Context ConstraintsOpenShift introduced security context constraints (SCC) before the introduction of pod security standards in Kubernetes. SCCs automatically make security modifications to pods when they are created. By default, the system:openshift:scc:restricted-v2 cluster role binding applies to all authenticated users, so regular user workloads use the restricted-v2 SCC. For example, when you execute the following command to create a workload without any security configuration, the SCC adds security configuration to the pods: [user@host ~]$ oc create deployment test --image registry.ocp4.example.com:8443/redhattraining/hello-world-nginx (You can add the --dry-run=client -o yaml options to view the deployment manifest. The deployment manifest does not contain the security properties, which are described later.)If you inspect the pods that the deployment created, the SCC makes the following changes: [user@host ~]$ oc get pod test-b8d5658b6-7bxfs -o yamlapiVersion: v1kind: Podmetadata: annotations:... output omitted... openshift.io/scc: restricted-v2 seccomp.security.alpha.kubernetes.io/pod: runtime/default...output omitted...spec: containers: - image: registry.ocp4.example.com:8443/redhattraining/hello-world-nginx imagePullPolicy: Always name: hello-world-nginx resources: {} securityContext: allowPrivilegeEscalation: false capabilities: drop: - ALL runAsNonRoot: true runAsUser: 1000690000... output omitted... securityContext: fsGroup: 1000690000 seLinuxOptions: level: s0:c26,c20 seccompProfile: type: RuntimeDefault... output omitted... These restrictions satisfy the restricted pod security policy.The result of these defaults means that when creating a workload (such as a deployment) in a namespace without any customization, the restricted pod security standard applies, but the admission controller only warns and audits. If the workload does not satisfy the pod security standard, then the admission controller allows the workload to be created, but prints a message such as the following warning: Warning: would violate PodSecurity "restricted:v1.24": allowPrivilegeEscalation != false (container "example" must set securityContext.allowPrivilegeEscalation=false), unrestricted capabilities (container "example" must set securityContext.capabilities.drop=["ALL"]), runAsNonRoot != true (pod or container "database" must set securityContext.runAsNonRoot=true), seccompProfile (pod or container "example" must set securityContext.seccompProfile.type to "RuntimeDefault" or "Localhost") However, by default Kubernetes creates the deployment pods with the restricted-v2 SCC, with the restrictions that the previous warning included. Due to the following factors, workloads generate only a warning, and the pod security standard admission controller allows their pods:The pod security standard admission controller never enforces pod security standards on workloads (only on pods).By default, namespaces do not enforce pod security standards on pods.By default, regular workloads create pods by using the restricted-v2 SCC, which satisfies the restricted pod security standard.Even if future versions of OpenShift change the default namespace configuration to enforce the restricted pod security standard, users will continue to be able to create workloads without explicitly declaring the restrictions that the pod security standard requires, because the restricted-v2 SCC will apply such restrictions automatically.You can take the following approaches to handling pod security:For most workloads, the restricted-v2 SCC limits pod privileges adequately. When creating a workload, you receive the warning, but the workload creates pods and works correctly.You can also create your workloads by providing a full specification of the security constraints to apply, without relying on the SCC to provide the configuration. By following this approach, privileges are more explicit, and you have greater control, so you can adjust more precisely the specific privileges that are granted to workloads.When the restricted-v2 SCC and the default restricted pod security standard are not adequate for your workload, because either you require further privileges, or you need further restrictions, you must use an existing SCC, or create a custom SCC, and provide explicit security specifications. You can also adjust the namespace labels to choose a different pod security standard, and decide to audit, log, or enforce the standard.
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Welcome to the Red Hat OpenShift Administration II (DO280) group in the Red Hat Learning Community!
Deanna
17 kwi 2023
We are excited to launch a space dedicated to the Red Hat Training course Red Hat OpenShift Administration II: Operating a Production Kubernetes Cluster!To gain the most value from this group - click the "Join Group" button in the upper right hand corner.We encourage group members to collaborate in this group to discuss topics, ask questions, share best practices and tips, provide course feedback, and share their accomplishments as it relates to DO280.Read more about Red Hat OpenShift Administration II here.Thanks!
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