Writing your first Ansible operator for OpenShift

@KeithResar WRITING YOUR FIRST _ANSIBLE OPERATOR_ FOR OPENSHIFT #ANSIBLEFEST

@KeithResar Operators are _application aware Kubernetes objects._ Active throughout the
application’s lifecycle, they manage instantiation, ongoing state, and destruction. #ANSIBLEFEST

@KeithResar FROM VISION TO _PROBLEM_ #ANSIBLEFEST

@KeithResar _problem:_ _turnkey management of stateless application_ _solution:_ _kubernetes (we
just saw this)_ _S2I, Helm_ #ANSIBLEFEST

@KeithResar _problem:_ _I’m a vendor or I create stateful apps,
_kubernetes doesn’t know anything about me_ #ANSIBLEFEST

@KeithResar etcd is a _distributed key value store_ that provides
a reliable way to store data across a cluster of machines. Stand-in for your app #ANSIBLEFEST

@KeithResar Create and Destroy • Resize • Failover Rolling upgrade
• Backup and Restore Stand-in for your app #ANSIBLEFEST

@KeithResar _problem:_ _I’m a vendor or I create stateful apps,
_kubernetes doesn’t know anything about me_ _solution:_ _create custom resource deﬁnitions (CRD)_ #ANSIBLEFEST

@KeithResar --- apiVersion: v1 kind: Service metadata: name: simpleapp spec:
ports: - name: 8080-tcp port: 8080 protocol: TCP targetPort: 8080 selector: deploymentconfig: simpleapp sessionAffinity: None type: ClusterIP deﬁning a _service_ resource service resources are a built in object type. #ANSIBLEFEST

@KeithResar --- apiVersion: etcd.database.coreos.com/v1beta2 kind: EtcdCluster metadata: name: example-etcd-cluster spec:
size: 3 version: 3.2.13 deﬁning an _EtcdCluster_ resource Our custom resource looks pretty similar. #ANSIBLEFEST

@KeithResar _problem:_ _golang isn’t going to ﬂy_ _solution:_ _skip go,
succeed with helm charts or ansible_ #ANSIBLEFEST

@KeithResar EVERY PROBLEM BRINGS A _SOLUTION_ #ANSIBLEFEST

@KeithResar DS AS API Server Cluster Workload Compare desired state
with actual state Reconcile process converges to desired state

@KeithResar DS AS API Server 01010001 01010010 10101011 01011001 0101001
01010001 01010010 10101011 01011001 0101001 Cluster Workload 01010001 01010010 10101011 01011001 0101001 1x simpleapp 2x simpleapp 01010001 01010010 10101011 01011001 0101001 #ANSIBLEFEST

@KeithResar DS AS API Server Cluster Workload Native K8s objects
like... Pods Services Deployments etc. #ANSIBLEFEST

@KeithResar AS DS _* operator_ watch reconcile action _________ _______________________
______ _____________________________ #ANSIBLEFEST

@KeithResar AS DS _Ansible operator_ watch reconcile ansible-runner _________ _______________________
______ _____________________________ Ansible playbook or role This is the only component you need to worry about! #ANSIBLEFEST

@KeithResar kubernetes layer application layer #ANSIBLEFEST

@KeithResar kubernetes layer ETCD pod ETCD pod Phase I Manage
native K8s objects application layer #ANSIBLEFEST

@KeithResar application layer kubernetes layer ETCD pod ETCD pod Phase
II Manage application objects 01001 etcd data 01001 etcd data #ANSIBLEFEST

@KeithResar A GIFT OF THE _DEMO_ TO YOU #ANSIBLEFEST

@KeithResar Demo Operator for data service _SimpleDB,_ that manages instantiation
and version upgrades. RBAC CRD CR DC #ANSIBLEFEST

@KeithResar Create service account, role, and role binding. Our operator
uses these to monitor events and reconcile desired and actual states. RBAC CRD CR DC #ANSIBLEFEST

______ _____________________________ #ANSIBLEFEST

@KeithResar Deﬁne the custom resource SimpleDB. This extends what Kubernetes
accepts, but doesn’t actually change any behavior. RBAC CRD CR DC #ANSIBLEFEST

@KeithResar Deﬁne and deploy the Ansible Operator container which executes
an ansible-runner process. RBAC CRD CR DC #ANSIBLEFEST

______ _____________________________ #ANSIBLEFEST

@KeithResar RBAC CRD CR DC # Dockerfile FROM quay.io/water-hole/ansible-operator USER
root RUN yum -y install MySQL-python && \ pip --no-cache-dir install dnspython COPY roles/ ${HOME}/roles/ COPY playbook.yaml ${HOME}/playbook.yaml COPY watches.yaml ${HOME}/watches.yaml #ANSIBLEFEST

______ _____________________________ #ANSIBLEFEST

@KeithResar RBAC CRD CR DC # Dockerfile FROM quay.io/water-hole/ansible-operator USER
root RUN yum -y install MySQL-python && \ pip --no-cache-dir install dnspython COPY roles/ ${HOME}/roles/ COPY playbook.yaml ${HOME}/playbook.yaml COPY watches.yaml ${HOME}/watches.yaml #ANSIBLEFEST

@KeithResar RBAC CRD CR DC # roles/SimpleDB/tasks/main.yml --- #ANSIBLEFEST

@KeithResar RBAC CRD CR DC # roles/SimpleDB/tasks/main.yml --- # …
(skip setting some variables) #ANSIBLEFEST

(skip setting some variables) # If no service defined then run our install playbook # This is idempotent so we could run it regardless - include_tasks: mariadb_install.yml when: mysql_ip == "NXDOMAIN" #ANSIBLEFEST

(skip setting some variables) # If no service defined then run our install playbook # This is idempotent so we could run it regardless - include_tasks: mariadb_install.yml when: mysql_ip == "NXDOMAIN" # Run our upgrade path if we need to change versions - include_tasks: mariadb_upgrade.yml when: version != version_query.json.version #ANSIBLEFEST

______ _____________________________ #ANSIBLEFEST

@KeithResar Instantiate our custom resource object. The operator is listening
for any SimpleDB events in our namespace. RBAC CRD CR DC #ANSIBLEFEST

@KeithResar RBAC CRD CR DC --- apiVersion: example.com/v1alpha1 kind: SimpleDB
metadata: name: simpledb spec: # Add fields here version: 1 #ANSIBLEFEST

______ _____________________________ Ansible playbook or role This is the only component you need to worry about! #ANSIBLEFEST

@KeithResar GO FARTHER WITH THESE _RESOURCES_ • OperatorHub • Introducing
the operator framework • water-hole’s ansible-operator repo • ansible-operator-demo repo • Awesome operators in the wild #ANSIBLEFEST

Writing your first Ansible operator for OpenShift

Writing your first Ansible operator for OpenShift

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