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--- lab:demonstrate_app_on_k8s [2023/04/23 19:16] – updated playbook user
+++ lab:demonstrate_app_on_k8s [2023/04/30 20:11] (current) – replaced user
@@ Line 1: / Line 1: @@
-====== Demonstrate App on k8s ======
-From [[NUC 1]], log in to the Ansible control node, [[NUC 2]].
-In our previous step we [[install_kubernetes|installed Kubernetes]] on our [[Stack of NUCs]].
-Now we are going to install a web app and expose it to our internal network.
-Purpose:
-  * Demonstrate a running a web application on Kubernetes
-References
-  * [[https://gitlab.com/doritoes/speedtester]]
-  * [[https://hub.docker.com/repository/docker/doritoes/speedtester/general]]
-  * [[https://docs.ansible.com/ansible/latest/collections/kubernetes/core/k8s_module.html]]
-Steps:
-  - Create distribution
-    * <file yaml speedtester-deployment.yaml>
-apiVersion: apps/v1
-kind: Deployment
-metadata:
-  name: speedtester
-  labels:
-    run: speedtester
-spec:
-  selector:
-    matchLabels:
-      run: speedtester
-  replicas: 2
-  template:
-    metadata:
-      labels:
-        run: speedtester
-    spec:
-      containers:
-      - name: speedtester
-        image: docker.io/doritoes/speedtester:latest
-        livenessProbe:
-          httpGet:
-            path: /favicon.ico
-            port: 80
-          initialDelaySeconds: 3
-          periodSeconds: 3
-</file>
-    * ''kubectl apply -f speedtester-deployment.yaml''
-  - View distribution information
-    * ''kubectl get pods''
-    * ''kubectl get deployment speedtester -o yaml''
-  - Increase number of replicas
-    *  Exit the file speedtester-deployment.yaml to set the number of replicas to the number of Kubernetes worker nodes you have
-    * ''kubectl apply-f speedtester-deployment.yaml''
-    * ''kubectl get pods -w''
-    * ''kubectl get deployments''
-    * ''kubectl describe deployments speedtester''
-    * ''kubectl get deployment speedtester -o yaml''
-  - Create a service
-    - Using expose
-      * ''kubectl expose deployment speedtester--port=8080 --name=speedtester-service --target-port=80''
-    - Using a manifest
-      * <file yaml speedtester-service.yaml>
-apiVersion: v1
-kind: Service
-metadata:
-  name: speedtester-service
-spec:
-  selector:
-    run: speedtester
-  type: NodePort
-  ports:
-    - protocol: TCP
-      port: 8080
-      targetPort: 80
-      notePort: 30080
-</file>
-      * ''kubectl apply -f speedtester-service.yaml''
-  - ''kubectl get all''
-  - ''kubectl describe svc speedtester-service''
-  - Test access
-    * point your web browser on [[NUC 1]] to the IP address of any node and the port we selected, port 300080
-    * Example: ''http://IPADDRESSWORKER:30080''
-  -  Alternative test from [[NUC 1]]
-    * ''kubectl port-forward speedtester 8080:80''
-    * point browser to [[https://localhost:8080]]
-====== Optional ======
-Perform some examples off automation using Ansible with Kubernetes
-  * restart pods?
-example from documentation is creating namespaces
-  * ''ansible web -m k8s -a "name=namespace2 state=present kind=Namespace api_version=v1"''
-===== Chaos Testing =====
-Proper chaos testing:
-[[https://opensource.com/article/21/6/chaos-kubernetes-kube-monkey]]
-Some small scale testing below.
-==== Kill Pods ====
-You can watch what's happening a couple of ways:
-  * ''watch kubectl get pods''
-  * ''kubectl get pods -w''
-Killing pods:
-  * watch pods terminating and creating
-Rebooting nodes:
-  * worker nodes show status unknown on pods, then return to running
-  * once in a while the random selection hits the master node
-    * watch to see what happens then
-=== Literally kill the first pod in the list ===
-<code bash>
-kubectl delete pod $(kubectl get pods -l run=speedtester -o jsonpath='{.items[0].metadata.name}')
-</code>
-=== Forever loop to keep killing the first pod on the list ===
-<code bash>
-while true; do
-kubectl delete pod $(kubectl get pods -l run=speedtester -o jsonpath='{.items[0].metadata.name}')
-done
-</code>
-=== Kill all the current pods ===
-This is slow because the loop structure is sequential.
-''ansible-playbook deletepod.yml''
-<file yaml deletepod.yml>
----
-- name: Delete current pods matching speedtester
-  hosts: localhost
-  vars:
-    pod_filter:
-      - speedtester # beginning of the pod name
-  gather_facts: false
-  tasks:
-    - name: Get a list of all pods from the namespace
-      command: kubectl get pods --no-headers -o custom-columns=":metadata.name"
-      register: pod_list
-    - name: Print pod names
-      debug:
-        msg: "{{ item }}"
-      loop: "{{ pod_list.stdout_lines }}"
-      when: item is match(pod_filter|join('|'))
-    - name: Delete matching pods
-      command: kubectl delete pod "{{ item }}"
-      loop: "{{ pod_list.stdout_lines }}"
-      when: item is match(pod_filter|join('|'))
-</file>
-Using async we can limit the waiting to see if the command returns.
-''ansible-playbook deletepod-async.yml''
-<file yaml deletepod-async.yml>
----
-- name: Delete current pods matching speedtester
-  hosts: localhost
-  vars:
-    pod_filter:
-      - speedtester # beginning of the pod name
-  gather_facts: false
-  tasks:
-    - name: Get a list of all pods from the namespace
-      command: kubectl get pods --no-headers -o custom-columns=":metadata.name"
-      register: pod_list
-    - name: Print pod names
-      debug:
-        msg: "{{ item }}"
-      loop: "{{ pod_list.stdout_lines }}"
-      when: item is match(pod_filter|join('|'))
-    - name: Delete matching pods
-      command: kubectl delete pod "{{ item }}"
-      async: 5 # timeout in seconds
-      poll: 1 # poll every second
-      loop: "{{ pod_list.stdout_lines }}"
-      when: item is match(pod_filter|join('|'))
-</file>
-==== Crash pods ====
-''ansible-playbook killpod-webservice.yml''
-<file yaml killpod-webservice.yml>
----
-- name: Crash current pods matching speedtester
-  hosts: localhost
-  vars:
-    pod_filter:
-      - speedtester # beginning of the pod name
-  gather_facts: false
-  tasks:
-    - name: Get a list of all pods from the namespace
-      command: kubectl get pods --no-headers -o custom-columns=":metadata.name"
-      register: pod_list
-    - name: Print pod names
-      debug:
-        msg: "{{ item }}"
-      loop: "{{ pod_list.stdout_lines }}"
-      when: item is match(pod_filter|join('|'))
-    - name: Stop nginx on the pod
-      command: kubectl exec "{{ item }}" -- pkill supervisord
-      async: 5 # timeout in seconds
-      poll: 1 # poll every second
-      loop: "{{ pod_list.stdout_lines }}"
-      when: item is match(pod_filter|join('|'))
-</file>
-==== Reboot a Random Ansible Node ====
-<file yaml randomreboot.yml>
----
-- hosts: localhost
-  connection: local
-  gather_facts: no
-  tasks:
-    - add_host:
-        name: "{{ item }}"
-        groups: limited_selection
-      loop: "{{ (groups['all'] | shuffle)[0:1] }}"
-- hosts: limited_selection
-  gather_facts: no
-  tasks:
-    - reboot:
-</file>