oc label node node1 env=dev
oc label node node2 env=prod
oc label node node1 env=test --overwrite
oc get nodes --show-labels
oc label node node1 env-
oc patch deployment/myapp \
--patch '{"spec":{"template":{"spec":{"nodeSelector":{"env":"dev"}}}}}'
oc adm new-project demo --node-selector "env=dev"
oc annotate namespace demo openshift.io/node-selector "env=dev" --overwrite
oc patch namespace demo \
--patch '{"metadata":{"annotations":{"openshift.io/node-selector": "env=dev"}}}'
oc adm taint nodes node1 dedicated=foo:NoSchedule -o json --dry-run=client |\
jq .spec.taints
[
{
"effect": "NoSchedule",
"key": "dedicated",
"value": "foo"
}
]
oc describe node node1 | grep -A2 Taint
Taints: dedicated=foo:NoSchedule
test=foo:NoSchedule
delete node taint
oc adm taint node node1 dedicated-
delete the other key
oc adm taint node node1 test-
list current node taints on the master node
oc get node/master0.nms.cp.fyre.ibm.com -o json |jq .spec.taints
[
{
"effect": "NoSchedule",
"key": "node-role.kubernetes.io/master"
}
]
Add a new taint foo:NoSchedule
oc adm taint nodes master0.nms.cp.fyre.ibm.com foo:NoSchedule
list the current taints, you can see the added taint
oc get node/master0.nms.cp.fyre.ibm.com -o json |jq .spec.taints
[
{
"effect": "NoSchedule",
"key": "foo"
},
{
"effect": "NoSchedule",
"key": "node-role.kubernetes.io/master"
}
]
lets delete the taint
oc adm taint nodes master0.nms.cp.fyre.ibm.com foo-
list the current taints - should be back to orignal starting point
oc get node/master0.nms.cp.fyre.ibm.com -o json |jq .spec.taints
[
{
"effect": "NoSchedule",
"key": "node-role.kubernetes.io/master"
}
]
Install htpasswd command line utility
sudo yum install httpd-tools
Create a new file for htpass with users and their passwords
htpasswd -c -b /tmp/htpass user1 password1
htpasswd -b /tmp/htpass user2 password2
Copy existing oauth config to a file for editing
oc get oauth cluster -o yaml > /tmp/oauth.yaml
Add httpasswd to oauth.yaml
spec:
identityProviders:
- name: localusers
type: HTPasswd
mappingMethod: claim
htpasswd:
fileData:
name: htpass-secret
Create a new secret which will hold the users and password file
oc create secret generic htpass-secret \
--from-file htpasswd=/tmp/htpass -n openshift-config
Now merge/replace existing oauth with edited version
oc replace -f /tmp/oauth.yaml
Watch the pods being replaced for the new config to take into affect
oc get po -w -n openshift-authentication
Lets delete user2 from htpass file
htpasswd -D /tmp/htpass user2
Update the secret with new htpass
oc set data secret/htpass-secret --from-file htpasswd=/tmp/htpass -n openshift-config
delete the user and identity from the system
oc delete user user2
oc delete identity localusers:user2
delete all users and identities defined in OAuth
oc delete user --all
oc delete identity --all
Assign cluster admin role to user
oc adm policy add-cluster-role-to-user cluster-admin user-name
Assign role at project/namespace level
oc policy add-role-to-user role-name user-name -n project-name
Get current clusterrolebindings configured for self-provisioners
oc get clusterrolebindings -o wide |grep -E "NAME|self-provisioners"
Describe the clusterrolebindings and clusterrole
oc describe clusterrolebindings self-provisioners
oc describe clusterrole self-provisioner
clusterrolebindings = self-provisioners
clusterrole = self-provisioner
Remove self-provisioner role from system such that authenticated users can't create projects
oc adm policy remove-cluster-role-from-group self-provisioner \
system:authenticated:oauth
Restore self-provisioners back to cluster as original
oc adm policy add-cluster-role-to-group \
--rolebinding-name self-provisioners self-provisioner system:authenticated:oauth
Creating new groups
oc adm group new dev-users dev1 dev2
oc adm group new qa-users qa1 qa2
Assign roles at namespace/project level. You will need admin role to assign users.
oc policy add-role-to-group edit dev-users -n namespace
oc policy add-role-to-group view qa-users -n namespace
oc policy add-role-to-user admin user1 -n namespace
Get all the rolebindings for the current namespace
oc get rolebindings -o wide
Make sure you have assigned cluster-admin to someone else before doing this!
oc adm policy add-cluster-role-to-user cluster-admin user-name
Instead of removing/deleting the user, we will remove the password from the system.
oc delete secret kubeadmin -n kube-system
Create secrets from literals and apply to a deployment
oc create secret generic secretname --from-literal key1=value1 \
--from-literal key2=value2
oc set env deployment/hello --from secret/secretname
Mount the secret file into the pod filesystem
oc set volume deployment/demo --add --type secret --secret-name demo-secret \
--mount-path /app-secrets
Example of setting env variables that contain sensitive data
oc create secret generic mysql \
--from-literal user=dba \
--from-literal password=redhat123 \
--from-literal database=test \
--from-literal hostname=mysql
oc new-app --name mysql \
--docker-image registry.access.redhat.com/rhscl/mysql-57-rhel7:5.7-47
oc set env deployment/mysql --prefix MYSQL_ --from secret/mysql
To use a private image in quay.io using secrets stored in files
podman login -u quay-username quay.io
oc create secret generic quayio \
--from-file .dockerconfigjson=${XDG_RUNTIME_DIR}/containers/auth.json \
--type kubernetes.io/dockerconfigjson
oc secrets link default quayio --for pull
oc import-image php --from quay.io/quay-username/php-70-rhel7 --confirm
Using openssl generate a private key and a public key
openssl req -x509 -newkey rsa:2048 -nodes -keyout cert.key -out cert.crt \
-subj "/C=US/ST=FL/L=Tampa/O=IBM/CN=*.apps.acme.com" -days 365
If additional subjectAtlName DNS extensions are needed
openssl req -x509 -newkey rsa:2048 -nodes -keyout cert.key -out cert.crt \
-subj "/C=US/ST=FL/L=Tampa/O=IBM/CN=*.apps.acme.com" -days 365 \
-addext "subjectAltName = DNS:host1.apps.acme.com,DNS:host2.apps.acme.com"
Using the key and cert create a TLS secret
oc create secret tls demo-certs --cert cert.crt --key cert.key
Mount the tls certs into the pod (using deployment)
oc set volume deployment/demo --add --type=secret --secret-name demo-tls \
--mount-path /usr/local/etc/ssl/certs --name tls-mount
Now create a passthrough route
oc create route passthrough demo-https --service demo-https --port 8443 \
--hostname demo-https.apps.ocp4.example.com
Using edge route with same certs
oc create route edge demo-https --service api-frontend --hostname api.apps.acme.com \
--key cert.key --cert cert.crt
Export the router cert in case we need to use it as a ca-cert
oc extract secrets/router-ca --keys tls.crt -n openshift-ingress-operator --to /tmp/
Get the current SCC roles defined
oc get scc
Get details of scc anyuid
oc describe scc anyuid
Create a service account in the current project and assign the anyuid priviledges to the service account.
oc create serviceaccount svc-name
oc adm policy add-scc-to-user anyuid -z svc-name -n namespace
oc set serviceaccount deployment/demo svc-name
review the scc priviledges needed for a pod
oc get po/podname-756ff-9cjbj -o yaml | oc adm policy scc-subject-review -f -
Example of gitlab being run as anyuid using serviceaccount
oc new-app --name gitlab --docker-image quay.io/redhattraiing/gitlab-ce:8.4.3-ce.0
oc get po/gitlab-6c5b5c5d55-gzkct -o yaml | oc adm policy scc-subject-review -f -
oc create sa gitlab-sa
oc adm policy add-scc-to-user anyuid -z gitlab-sa
oc set sa deployment/gitlab gitlab-sa
Check the node resources
oc describe node node1
Set resources on a deployment. Request limits are how much each request is allowed, and limit is the max allowed
oc set resources deployment hello-world-nginx \
--requests cpu=10m,memory=20Mi --limits cpu=180m,memory=100Mi
Scheduling decisions are made based on the request to ensure that a node has enough capacity available to meet the requested value. If a container specifies limits, but omits requests, the requests are defaulted to the limits. A container is not able to exceed the specified limit on the node. The enforcement of limits is dependent upon the compute resource type. If a container makes no request or limit, the container is scheduled to a node with no resource guarantees.
Quota is project level resources available
oc create quota dev-quota --hard services=10,cpu=1300m,memory=1.5Gi
Quota including requests and limits at namespace level. Remember if you don't provide requests values, then same limits values are used for both requests and limits
oc create quota my-quota --hard pods=10,requests.cpu=2,requests.memory=1Gi,limits.cpu=4,limits.memory=2Gi
Cluster Quota is resources available across multiple projects
oc create clusterquota env-qa \
--project-annotation-selector.openshift.io/requester=qa \
--hard pods=12,secrets=20,services=5
Show all project annotations and labels
oc describe namespace demo
Limit ranges in a yaml file are defined as follows
apiVersion: "v1"
kind: "LimitRange"
metadata:
name: "nms-limits"
spec:
limits:
- type: "Pod"
max:
cpu: "2"
memory: "1Gi"
min:
cpu: "200m"
memory: "6Mi"
- type: "Container"
max:
cpu: "2"
memory: "1Gi"
min:
cpu: "100m"
memory: "4Mi"
default: # default if not specified in the Pod spec
cpu: "300m"
memory: "200Mi"
defaultRequest: # default request if not specified in the Pod spec
cpu: "200m"
memory: "100Mi"
oc create -f limitranges.yaml -n net-ingress
oc describe limits nms-limits -n net-ingress
Name: nms-limits
Namespace: net-ingress
Type Resource Min Max Default Request Default Limit Max Limit/Request Ratio
---- -------- --- --- --------------- ------------- -----------------------
Pod cpu 200m 2 - - -
Pod memory 6Mi 1Gi - - -
Container cpu 100m 2 200m 300m -
Container memory 4Mi 1Gi 100Mi 200Mi -
oc scale --replicas 3 deployment/demo
oc autoscale dc/demo --min 1 --max 10 --cpu-percent 80
oc get hpa
- Readiness: How long before container is ready to serve requests. If probe fails Openshift removes the IP from the services endpoints, such that no traffic is forwarded to the container.
- Liveness: Probe to test if container is in healthy state? If probe fails, Openshift kills the conatiner and redeploys.
Probes have the following configuration settings:
- initialDelaySeconds: required, default value=0, how long to wait to start the probe after container starts
- timeoutSeconds: required, default value=1, how long to wait for the probe to finish
- periodSeconds: not required, default value=10, how often to probe
- successThreshold: not required, default value=1, min consecutive successes after failure to consider success
- failureThreshold: not required, default value=3, min consecutive failures to be considered a failure
Examples of setting probes:
oc set probe dc/demo --readiness --initial-delay-seconds 20
oc set probe dc/webapp --readiness --get-url=http://:8080/healthz \
--period-seconds 10 --timeout-seconds 1 --initial-delay-seconds 30
oc set probe dc/mq --liveness --open-tcp 1414 --period-seconds 3 \
--timeout-seconds 2 --failure-threshold 3 --initial-delay-seconds 30
oc set probe dc/ace --liveness --get-url http://:7600/healthz \
--initial-delay-seconds 30 --period-seconds 10 --dry-run=client -o json | \
jq .spec.template.spec.containers[].livenessProbe
{
"httpGet": {
"path": "/healthz",
"port": 7600,
"scheme": "HTTP"
},
"initialDelaySeconds": 30,
"periodSeconds": 10
}
oc set probe dc/mq --liveness --open-tcp 1414 --period-seconds 3 \
--timeout-seconds 2 --failure-threshold 3 --initial-delay-seconds 30 \
--dry-run=client -o json | jq .spec.template.spec.containers[].livenessProbe
{
"tcpSocket": {
"port": 1414
},
"initialDelaySeconds": 30,
"timeoutSeconds": 2,
"periodSeconds": 3,
"failureThreshold": 3
}
Removing probes:
oc set probe dc/demo --remove --readiness --liveness
Built in registry is housed in openshift-image-registry namespace
oc -n openshift-image-registry get svc
cluster wide svc naming scheme is service-name.namespace.svc
image-registry.openshift-image-registry.svc
using stored images from openshift project
oc get images
oc get is -n openshift | grep httpd
oc new-app --name nms --docker-image \
image-registry.openshift-image-registry.svc:5000/openshift/httpd:latest
OR
oc new-app --name nms \
image-registry.openshift-image-registry.svc:5000/openshift/httpd:latest
OR
oc new-app --name nms --image \
image-registry.openshift-image-registry.svc:5000/openshift/httpd:latest
create a service
oc expose deployment/nms --port 8080 --target-port 8080
Using a docker strategy using local build directory
oc new-app --strategy docker --binary --name myapp
oc start-build myapp --from-dir . --follow
oc expose deployment myapp --target-port 8080 --port 80 <br/?
oc expose svc myapp
Using a nodejs builder
oc new-app --binary --image-stream nodejs --name nodejs
oc start-build nodejs --from-dir . --follow
oc expose svc/nodejs
Following are high level issues that are highlighted in the course
- Limits or Quotas are exceeded
- Taints on node (NoSchedule)
- Route is misconfigured
- Permissions missing, assign SA to deployment
Useful commands.
oc logs pod-name
oc adm top pods
oc adm top nodes
oc get events --field-selector type=Warning
oc debug pod
oc debug node/nodename
oc adm taint node node-name key-
Connect to a service using a debug image
oc get svc/mysql -o jsonpath="{.spec.clusterIP}{'\n'}"
oc debug -t deployment/app --image registry.access.redhat.com/ubi8/ubi:8.0
curl -v telnet://<clusterIP-from-above>:<port-number>
After fixing the deployment (yaml or the issue at hand), the deployment might have timed out by the time the issue was fixed. In order to push the deployment a new "rollout" might be needed.
oc rollout latest dc/demo
or
oc rollout latest deployment/demo
An example app was deployed where the endpoint wasn't working. After troubleshooting it was found the name of the service was defined with app tagname was mis spelled. Had to fix the typo to get the service working again.
Another case was where instead of Route an Ingress with the wrong hostname was defined. When you delete the route, the route was re-created by openshift with a different route-name but still having the wrong hostname. To fix, we had to edit the Ingress configuration with the correct hostname. Once that was done, the correct route was generated and started working!
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