https://github.com/ocdbytes/kubernetes_basics
This is a Kubernetes Cheatsheet kind of to revise the concepts time to time and contains all the basic operations performed in kubernetes and all the basic features such as load balancing and pods concept
https://github.com/ocdbytes/kubernetes_basics
kubernetes kubernetes-cluster kubernetes-deployment
Last synced: 11 months ago
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This is a Kubernetes Cheatsheet kind of to revise the concepts time to time and contains all the basic operations performed in kubernetes and all the basic features such as load balancing and pods concept
- Host: GitHub
- URL: https://github.com/ocdbytes/kubernetes_basics
- Owner: ocdbytes
- Created: 2022-06-11T09:30:09.000Z (over 3 years ago)
- Default Branch: main
- Last Pushed: 2023-05-02T21:19:02.000Z (almost 3 years ago)
- Last Synced: 2024-04-14T10:46:08.888Z (almost 2 years ago)
- Topics: kubernetes, kubernetes-cluster, kubernetes-deployment
- Homepage:
- Size: 867 KB
- Stars: 0
- Watchers: 2
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# Kubernetes Basics ⛵
In docker we faced a problem called container orchestration so for solution of that there was docker swarm but another solution offered by google is **Kubernetes**
Now to set up we can use GCP, Azure or **LINODE**
We can configure our Kubernetes using Linode cloud provider →
[https://cloud.linode.com/kubernetes/create](https://cloud.linode.com/kubernetes/create)
Now fill the details and create a node
Now after creating we will get a master node link and three nodes which we selected
Now we need to install kubectl on our host machine which is required for using kubernetes.
```bash
curl -LO https://storage.googleapis.com/kubernetes-release/release/$(curl -s https://storage.googleapis.com/kubernetes-release/release/stable.txt)/bin/linux/amd64/kubectl
```
→
```bash
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 43.5M 100 43.5M 0 0 7513k 0 0:00:05 0:00:05 --:--:-- 8750k
```
Now in the directory we have our kubectl and we need to configure it now →
```bash
chmod +x kubectl
sudo mv ./kubectl /usr/local/bin/kubectl
```
Now copy our kubernetes yaml config file
```bash
nano kubeconfig.yaml
```
And here paste it and save the file
→ Export the file name as a variable
```bash
export KUBECONFIG=kubeconfig.yaml
```
## For MacOS
```bash
brew install kubectl
# This will install and link the kubectl to CLI
```
→ Now continuing
### To get the nodes on the cluster (for this to work we need to specify our kubeconfig.yaml file )
```bash
kubectl get nodes
```
→ Get nodes
```bash
NAME STATUS ROLES AGE VERSION
lke63625-98873-62a469e5f73b Ready 133m v1.23.6
lke63625-98873-62a469e6c87d Ready 133m v1.23.6
lke63625-98873-62a469e795e1 Ready 133m v1.23.6
```
### To get info about the cluster
```bash
kubectl cluster-info
```
→
```bash
Kubernetes control plane is running at https://c9abbb71-4d6e-4e08-b874-e99614d81203.ap-west-2.linodelke.net:443
KubeDNS is running at https://c9abbb71-4d6e-4e08-b874-e99614d81203.ap-west-2.linodelke.net:443/api/v1/namespaces/kube-system/services/kube-dns:dns/proxy
To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'.
```
### To run our image
```bash
kubectl run --image= --port=
```
This will run our application in a pod
### To get pods running
```bash
kubectl get pods
```
### To get the more info about the running pods
```bash
kubectl describe pods
```
## Deployment
Now if we want to deploy our machine to the worker nodes and we want to specify what we need in each node then we need to do it by defining in a yaml file
For eg:
```yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: networkchuckcoffee-deployment
labels:
app: nccoffee
spec:
replicas: 3
selector:
matchLabels:
app: nccoffee
template:
metadata:
labels:
app: nccoffee
spec:
containers:
- name: nccoffee
image: thenetworkchuck/nccoffee:pourover
imagePullPolicy: Always
ports:
- containerPort: 80
```
To deploy using the config defined by us in this yaml file we will use this command
```bash
kubectl apply -f
```
### Delete a pod
```bash
kubectl delete pods
```
### Get deployments
```bash
kubectl get deployments
```
### Edit deployment
Now in kubernetes it always keeps checking that how our deployment is performing like if I specified i need 3 replicas of my application then it keeps ensuring that I need 3 instances of our application running all the time
We can also edit our deployment by editing the file
```bash
kubectl get deployments
kubectl edit deployment
```
### Getting more details or pods
```bash
kubectl get pods -o wide
```
## Service
Now if we need to make our website accessible to whole over the internet then we need to expose our container and for that we will user service and it will also act as an load balancer
service example
```yaml
apiVersion: v1
kind: Service
metadata:
name: coffee-service
annotations:
service.beta.kubernetes.io/linode-loadbalancer-throttle: "4"
labels:
app: coffee-service
spec:
type: LoadBalancer
ports:
- name: http
port: 80
protocol: TCP
targetPort: 80
selector:
app: nccoffee
sessionAffinity: None
```
→
```bash
nano coffee-service.yaml
kubectl apply -f coffee-service.yaml
```
### Get running services
```bash
kubectl get services
```
For more details about a service
```bash
kubectl describe services
```
---
Requirements
```bash
- Kubernetes
- Minikube
- Docker
```
Configure minikube
```bash
minikube start --driver=docker
--------
😄 minikube v1.30.1 on Darwin 13.3.1
✨ Using the docker driver based on user configuration
📌 Using Docker Desktop driver with root privileges
👍 Starting control plane node minikube in cluster minikube
🚜 Pulling base image ...
> gcr.io/k8s-minikube/kicbase...: 373.53 MiB / 373.53 MiB 100.00% 2.84 Mi
🔥 Creating docker container (CPUs=2, Memory=2200MB) ...
🐳 Preparing Kubernetes v1.26.3 on Docker 23.0.2 ...
▪ Generating certificates and keys ...
▪ Booting up control plane ...
▪ Configuring RBAC rules ...
🔗 Configuring bridge CNI (Container Networking Interface) ...
▪ Using image gcr.io/k8s-minikube/storage-provisioner:v5
🔎 Verifying Kubernetes components...
🌟 Enabled addons: storage-provisioner, default-storageclass
🏄 Done! kubectl is now configured to use "minikube" cluster and "default" namespace by default
--------
minikube status # tells us about the status of server
--------
minikube
type: Control Plane
host: Running
kubelet: Running
apiserver: Running
kubeconfig: Configured
--------
minikube ip # tells us about the server ip
```
ssh - minikube
```bash
minikube ssh
```
```bash
λ ~ kubectl get nodes
NAME STATUS ROLES AGE VERSION
minikube Ready control-plane 3m28s v1.26.3
λ ~ kubectl get namespaces
NAME STATUS AGE
default Active 4m11s
kube-node-lease Active 4m15s
kube-public Active 4m15s
kube-system Active 4m16s
λ ~ kubectl get pods --namespace=kube-system
NAME READY STATUS RESTARTS AGE
coredns-787d4945fb-dmxln 1/1 Running 0 4m53s
etcd-minikube 1/1 Running 0 5m5s
kube-apiserver-minikube 1/1 Running 0 5m4s
kube-controller-manager-minikube 1/1 Running 0 5m4s
kube-proxy-8w89j 1/1 Running 0 4m54s
kube-scheduler-minikube 1/1 Running 0 5m5s
storage-provisioner 1/1 Running 0 4m47s
```
creating pods
```bash
kubectl run nginx --image=nginx
```
pod commands
```bash
kubectl describe pod nginx
```
Accessing the container
- minikube ssh
```bash
docker@minikube:~$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
22b0ac286045 nginx "/docker-entrypoint.…" 5 minutes ago Up 5 minutes k8s_nginx_nginx_default_c8bc183a-de0f-4d02-a435-63b2d3e20747_0
2e0411f739c0 registry.k8s.io/pause:3.9 "/pause" 5 minutes ago Up 5 minutes k8s_POD_nginx_default_c8bc183a-de0f-4d02-a435-63b2d3e20747_0
a0db5789e937 6e38f40d628d "/storage-provisioner" 12 minutes ago Up 12 minutes k8s_storage-provisioner_storage-provisioner_kube-system_fab2000e-95c1-4025-8f28-74aba9665cbb_0
61446f64c99d registry.k8s.io/pause:3.9 "/pause" 12 minutes ago Up 12 minutes k8s_POD_storage-provisioner_kube-system_fab2000e-95c1-4025-8f28-74aba9665cbb_0
32db8541dfe5 5185b96f0bec "/coredns -conf /etc…" 12 minutes ago Up 12 minutes k8s_coredns_coredns-787d4945fb-dmxln_kube-system_46e5799d-389b-4e1e-b2f0-5bd29a8f4dd9_0
47721954f2a4 registry.k8s.io/pause:3.9 "/pause" 12 minutes ago Up 12 minutes k8s_POD_coredns-787d4945fb-dmxln_kube-system_46e5799d-389b-4e1e-b2f0-5bd29a8f4dd9_0
2c2ac7f8ab18 92ed2bec97a6 "/usr/local/bin/kube…" 12 minutes ago Up 12 minutes k8s_kube-proxy_kube-proxy-8w89j_kube-system_74106fb9-4459-4ffe-85a9-3815b4f1df71_0
e6011c45a1f7 registry.k8s.io/pause:3.9 "/pause" 12 minutes ago Up 12 minutes k8s_POD_kube-proxy-8w89j_kube-system_74106fb9-4459-4ffe-85a9-3815b4f1df71_0
21ce2445eb26 fce326961ae2 "etcd --advertise-cl…" 13 minutes ago Up 13 minutes k8s_etcd_etcd-minikube_kube-system_d59d6e9872abe47b5a2578072778f755_0
d4992ed31fc3 1d9b3cbae03c "kube-apiserver --ad…" 13 minutes ago Up 13 minutes k8s_kube-apiserver_kube-apiserver-minikube_kube-system_2000cc64446a6d814c0e4a3fd7eefdb7_0
a8b3031c53ff 5a7904736932 "kube-scheduler --au…" 13 minutes ago Up 13 minutes k8s_kube-scheduler_kube-scheduler-minikube_kube-system_0818f4b1a57de9c3f9c82667e7fcc870_0
8ae3c06858b6 ce8c2293ef09 "kube-controller-man…" 13 minutes ago Up 13 minutes k8s_kube-controller-manager_kube-controller-manager-minikube_kube-system_466b9e73e627277a8c24637c2fa6442d_0
c34c6e9c1f9b registry.k8s.io/pause:3.9 "/pause" 13 minutes ago Up 13 minutes k8s_POD_kube-scheduler-minikube_kube-system_0818f4b1a57de9c3f9c82667e7fcc870_0
1e60619d6362 registry.k8s.io/pause:3.9 "/pause" 13 minutes ago Up 13 minutes k8s_POD_kube-controller-manager-minikube_kube-system_466b9e73e627277a8c24637c2fa6442d_0
15f33b952657 registry.k8s.io/pause:3.9 "/pause" 13 minutes ago Up 13 minutes k8s_POD_kube-apiserver-minikube_kube-system_2000cc64446a6d814c0e4a3fd7eefdb7_0
fa29ac8194be registry.k8s.io/pause:3.9 "/pause" 13 minutes ago Up 13 minutes k8s_POD_etcd-minikube_kube-system_d59d6e9872abe47b5a2578072778f755_0
docker@minikube:~$ docker ps | grep "nginx"
22b0ac286045 nginx "/docker-entrypoint.…" 5 minutes ago Up 5 minutes k8s_nginx_nginx_default_c8bc183a-de0f-4d02-a435-63b2d3e20747_0
2e0411f739c0 registry.k8s.io/pause:3.9 "/pause" 5 minutes ago Up 5 minutes k8s_POD_nginx_default_c8bc183a-de0f-4d02-a435-63b2d3e20747_0
docker@minikube:~$ docker exec -it 22b0ac286045 sh
# hostname
nginx
# ls
bin boot dev docker-entrypoint.d docker-entrypoint.sh etc home lib lib64 media mnt opt proc root run sbin srv sys tmp usr var
#
```
```bash
λ ~ kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
nginx 1/1 Running 0 9m41s 10.244.0.3 minikube
```
```bash
λ ~ kubectl delete pod nginx
pod "nginx" deleted
```
Creating the deployments
```bash
λ ~ kubectl create deployment nginx --image=nginx
deployment.apps/nginx created
```
```bash
λ ~ kubectl describe deployment nginx
Name: nginx
Namespace: default
CreationTimestamp: Wed, 03 May 2023 01:11:54 +0530
Labels: app=nginx
Annotations: deployment.kubernetes.io/revision: 1
Selector: app=nginx
Replicas: 1 desired | 1 updated | 1 total | 1 available | 0 unavailable
StrategyType: RollingUpdate
MinReadySeconds: 0
RollingUpdateStrategy: 25% max unavailable, 25% max surge
Pod Template:
Labels: app=nginx
Containers:
nginx:
Image: nginx
Port:
Host Port:
Environment:
Mounts:
Volumes:
Conditions:
Type Status Reason
---- ------ ------
Available True MinimumReplicasAvailable
Progressing True NewReplicaSetAvailable
OldReplicaSets:
NewReplicaSet: nginx-748c667d99 (1/1 replicas created)
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal ScalingReplicaSet 102s deployment-controller Scaled up replica set nginx-748c667d99 to 1
```
scaling
```bash
λ ~ kubectl scale deployment nginx --replicas=5
deployment.apps/nginx scaled
λ ~ kubectl get pods
NAME READY STATUS RESTARTS AGE
nginx-748c667d99-47gjc 0/1 ContainerCreating 0 6s
nginx-748c667d99-5c7kx 1/1 Running 0 8m36s
nginx-748c667d99-grxrn 0/1 ContainerCreating 0 6s
nginx-748c667d99-ncfxt 0/1 ContainerCreating 0 6s
nginx-748c667d99-t9htq 0/1 ContainerCreating 0 6s
```
```bash
λ ~ kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
nginx-748c667d99-47gjc 1/1 Running 0 67s 10.244.0.5 minikube
nginx-748c667d99-5c7kx 1/1 Running 0 9m37s 10.244.0.4 minikube
nginx-748c667d99-grxrn 1/1 Running 0 67s 10.244.0.6 minikube
nginx-748c667d99-ncfxt 1/1 Running 0 67s 10.244.0.7 minikube
nginx-748c667d99-t9htq 1/1 Running 0 67s 10.244.0.8 minikube
```
```bash
λ ~ kubectl scale deployment nginx --replicas=3
deployment.apps/nginx scaled
λ ~ kubectl get pods
NAME READY STATUS RESTARTS AGE
nginx-748c667d99-5c7kx 1/1 Running 0 11m
nginx-748c667d99-grxrn 1/1 Running 0 2m49s
nginx-748c667d99-t9htq 1/1 Running 0 2m49s
λ ~ kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
nginx-748c667d99-5c7kx 1/1 Running 0 11m 10.244.0.4 minikube
nginx-748c667d99-grxrn 1/1 Running 0 2m55s 10.244.0.6 minikube
nginx-748c667d99-t9htq 1/1 Running 0 2m55s 10.244.0.8 minikube
```
Exposing the application
```bash
λ ~ kubectl expose deployment nginx --port=8080 --target-port=80
service/nginx exposed
λ ~ kubectl get service
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 443/TCP 42m
nginx ClusterIP 10.107.176.110 8080/TCP 20s
```
This is exposed to the kubernetes cluster.
```bash
λ ~ kubectl describe service nginx
Name: nginx
Namespace: default
Labels: app=nginx
Annotations:
Selector: app=nginx
Type: ClusterIP
IP Family Policy: SingleStack
IP Families: IPv4
IP: 10.107.176.110
IPs: 10.107.176.110
Port: 8080/TCP
TargetPort: 80/TCP
Endpoints: 10.244.0.4:80,10.244.0.6:80,10.244.0.8:80
Session Affinity: None
Events:
```
Exposing to the system outside the clusters
```bash
kubectl expose deployment --type=NodePort --port=3000
kubectl expose deployment --type=LoadBalancer --port=3000
```