OpenShift Examples¶

Run OpenShift on your Hetzner Server¶

https://github.com/RedHat-EMEA-SSA-Team/hetzner-ocp4

Run OCP on your laptop¶

OpenShift 4¶

OpenShift 3¶

Container Development Kit

Or simple oc cluster up

oc cluster up --image=registry.access.redhat.com/openshift3/ose \
  --public-hostname=localhost

Usefull Red Hat Solutions article¶

Article	Note
How can a user update OpenShift 4 console route
Red Hat Operators Supported in Disconnected Mode
Support Policies for Red Hat OpenShift Container Platform Clusters - Deployments Spanning Multiple Sites(Data Centers/Regions)
Red Hat OpenShift Container Platform Update Graph
Consolidated Troubleshooting Article OpenShift Container Platform 4.x
Red Hat Container Support Policy
Red Hat Enterprise Linux Container Compatibility Matrix
Consolidated Troubleshooting Article OpenShift Container Platform 4.x
Red Hat OpenShift Container Platform Life Cycle Policy

Glossary¶

Term	Definition
Container runtime	Container runtimes, or specificially OCI Runtimes are things like runc, crun, kata, gvisor.
Container engines	Container Engines pull and push container images from container registries, configure OCI Runtime Specifications and launch OCI Runtimes. For example CRI-O, ContainerD

Usefull commands¶

Easy install jq on RHEL¶

curl -O -L https://github.com/stedolan/jq/releases/download/jq-1.6/jq-linux64
chmod +x jq-linux64
sudo mv jq-linux64 /usr/local/bin/jq

jq examples¶

PVC CSV

oc get pvc --all-namespaces -o json | jq -r  ' .items[] |  [.metadata.namespace,.metadata.name,.status.capacity.storage|tostring]|@csv'

Print certificate from secret¶

oc get secret -n openshift-web-console webconsole-serving-cert -o json | jq -r '.data."tls.crt"' | base64 -d > foo.pem
# Can't use openssl x509, x509 do not support bundles
openssl crl2pkcs7 -nocrl -certfile foo.pem | openssl pkcs7 -print_certs  -noout

Check certificate from master-api¶

echo -n | openssl s_client -connect q.bohne.io:8443 -servername q.bohne.io 2>/dev/null | openssl x509 -noout -subject -issuer

OpenShift certificate overview:¶

find /etc/origin/master/ /etc/origin/node -name "*.crt" -printf '%p - ' -exec openssl x509 -noout -subject -in {} \;

kubectl/oc patch¶

For example:

oc patch configs.imageregistry.operator.openshift.io/cluster \
    --type='json' \
    --patch='[
        {"op": "replace", "path": "/spec/managementState", "value": "Managed"},
        {"op": "replace", "path": "/spec/rolloutStrategy", "value": "Recreate"},
        {"op": "replace", "path": "/spec/storage", "value": {"pvc":{"claim": "image-registry-pvc" }}}
    ]'

patch definition:

JSON Merge Patch RFC 7386: https://tools.ietf.org/html/rfc7386
JSON Patch RFC 6902: https://tools.ietf.org/html/rfc6902
The JSONPath websites offers a good description which operation can be used an how: http://jsonpatch.com/

Blog post: https://labs.consol.de/development/2019/04/08/oc-patch-unleashed.html

Commands inside a POD¶

Get IP Addresses without ip or ifconfig?¶

Command¶

1	`cat /proc/net/fib_trie`

Sample outpout¶

$ cat /proc/net/fib_trie
Main:
  +-- 0.0.0.0/0 3 0 4
     +-- 0.0.0.0/4 2 0 2
        |-- 0.0.0.0
           /0 universe UNICAST
        +-- 10.128.0.0/14 2 0 2
           |-- 10.128.0.0
              /14 universe UNICAST
           +-- 10.131.0.0/23 2 0 2
              +-- 10.131.0.0/28 2 0 2
                 |-- 10.131.0.0
                    /32 link BROADCAST
                    /23 link UNICAST
                 |-- 10.131.0.14
                    /32 host LOCAL
              |-- 10.131.1.255
                 /32 link BROADCAST
     +-- 127.0.0.0/8 2 0 2
        +-- 127.0.0.0/31 1 0 0
           |-- 127.0.0.0
              /32 link BROADCAST
              /8 host LOCAL
           |-- 127.0.0.1
              /32 host LOCAL
        |-- 127.255.255.255
           /32 link BROADCAST
     |-- 172.30.0.0
        /16 universe UNICAST
     |-- 224.0.0.0
        /4 universe UNICAST
Local:
  +-- 0.0.0.0/0 3 0 4
     +-- 0.0.0.0/4 2 0 2
        |-- 0.0.0.0
           /0 universe UNICAST
        +-- 10.128.0.0/14 2 0 2
           |-- 10.128.0.0
              /14 universe UNICAST
           +-- 10.131.0.0/23 2 0 2
              +-- 10.131.0.0/28 2 0 2
                 |-- 10.131.0.0
                    /32 link BROADCAST
                    /23 link UNICAST
                 |-- 10.131.0.14
                    /32 host LOCAL
              |-- 10.131.1.255
                 /32 link BROADCAST
     +-- 127.0.0.0/8 2 0 2
        +-- 127.0.0.0/31 1 0 0
           |-- 127.0.0.0
              /32 link BROADCAST
              /8 host LOCAL
           |-- 127.0.0.1
              /32 host LOCAL
        |-- 127.255.255.255
           /32 link BROADCAST
     |-- 172.30.0.0
        /16 universe UNICAST
     |-- 224.0.0.0
        /4 universe UNICAST

Command¶

1	`cat /proc/net/fib_trie \| grep "\|--" \| egrep -v "0.0.0.0\| 127."`

Sample output¶

$ cat /proc/net/fib_trie | grep "|--"   | egrep -v "0.0.0.0| 127."
           |-- 10.128.0.0
                 |-- 10.131.0.0
                 |-- 10.131.0.14
              |-- 10.131.1.255
     |-- 172.30.0.0
     |-- 224.0.0.0
           |-- 10.128.0.0
                 |-- 10.131.0.0
                 |-- 10.131.0.14
              |-- 10.131.1.255
     |-- 172.30.0.0
     |-- 224.0.0.0

cURL & Kubernetes/OpenShift API examples¶

$ curl --cacert /run/secrets/kubernetes.io/serviceaccount/ca.crt \
  --header "Authorization: Bearer $(cat /run/secrets/kubernetes.io/serviceaccount/token)" \
  https://kubernetes.default.svc.cluster.local/version

{
  "major": "1",
  "minor": "16+",
  "gitVersion": "v1.16.2",
  "gitCommit": "4320e48",
  "gitTreeState": "clean",
  "buildDate": "2020-01-21T19:50:59Z",
  "goVersion": "go1.12.12",
  "compiler": "gc",
  "platform": "linux/amd64"
}

List all Services from ansible-service-broker¶

 curl -k -s $(oc get broker ansible-service-broker -o go-template='{{.spec.url}}v2/catalog') | jq ' .services[] | {Name: .name, displayName: .metadata.displayName}'
{
  "Name": "dh--latest",
  "displayName": "Hello World (APB)"
}

List all services from template broker:¶

curl -s -k -X GET -H "Authorization: Bearer $(oc whoami -t)" -H "X-Broker-Api-Version: 2.7"  https://192.168.37.1:8443/brokers/template.openshift.io/v2/catalog | jq ' .services[] | {Name: .name, displayName: .metadata.displayName}'

List all services from service catalog¶

curl -s -k -X GET -H "Authorization: Bearer $(oc whoami -t)" https://192.168.37.1:8443/apis/servicecatalog.k8s.io/v1alpha1/serviceclasses | jq ' .items[] | { brokerName: .brokerName, name: .metadata.name, displayName: .externalMetadata.displayName } '

Stargazers over time¶

Last update: November 7, 2022