Namrata MU – Best DevOps

Replica sets with example and commands

Namrata MU — Thu, 16 Sep 2021 06:52:58 +0000

[centos@ip-172-31-22-14 ~]$ kubectl scale –replicas=1 deploy/namrata -n=namtest
deployment.apps/namrata scaled
[centos@ip-172-31-22-14 ~]$ kubectl scale –replicas=10 deploy/namrata -n=namtest
deployment.apps/namrata scaled
[centos@ip-172-31-22-14 ~]$ kubectl get deploy -n=namrata
No resources found in namrata namespace.
[centos@ip-172-31-22-14 ~]$ kubectl get deploy -n=namtest
NAME READY UP-TO-DATE AVAILABLE AGE
namrata 10/10 10 10 8m54s
namrata1 3/3 3 3 6m40s
[centos@ip-172-31-22-14 ~]$ kubectl get pods -n=namtest
NAME READY STATUS RESTARTS AGE
namrata 1/1 Running 0 116m
namrata-dfb987696-798c7 1/1 Running 0 2m5s
namrata-dfb987696-8b6kz 1/1 Running 0 2m5s
namrata-dfb987696-bzxsx 1/1 Running 0 2m5s
namrata-dfb987696-d9qsq 1/1 Running 0 2m5s
namrata-dfb987696-gdmwn 1/1 Running 0 2m5s
namrata-dfb987696-gwgfr 1/1 Running 0 2m5s
namrata-dfb987696-lxf69 1/1 Running 0 10m
namrata-dfb987696-qtt8c 1/1 Running 0 2m5s
namrata-dfb987696-tvz9j 1/1 Running 0 2m5s
namrata-dfb987696-xn7wc 1/1 Running 0 2m5s
namrata1-b5dc88477-7f9q9 1/1 Running 0 8m22s
namrata1-b5dc88477-9jhk7 1/1 Running 0 8m22s
namrata1-b5dc88477-lm2r4 1/1 Running 0 8m22s
[centos@ip-172-31-22-14 ~]$ kubectl get rs -n=namtest
NAME DESIRED CURRENT READY AGE
namrata-dfb987696 10 10 10 10m
namrata1-b5dc88477 3 3 3 8m31s
[centos@ip-172-31-22-14 ~]$ kubectl describe po
Name: nagesh
Namespace: default
Priority: 0
Node: ip-172-31-26-110.ap-south-1.compute.internal/172.31.26.110
Start Time: Thu, 16 Sep 2021 04:50:59 +0000
Labels: app=helloworld
Annotations:
Status: Running
IP: 10.44.0.4
IPs:
IP: 10.44.0.4
Containers:
nagesh:
Container ID: docker://79ba529d343accf9ee69a1b1a08ca9ae6b7f8e87d338f99c06ef17cb020a6b9d
Image: scmgalaxy/nginx-devopsschoolv1
Image ID: docker-pullable://scmgalaxy/nginx-devopsschoolv1@sha256:0544f1e7eb70ee9967819f1655160f5457d47aa24910a32f357c1a41aab3d20b
Port: 80/TCP
Host Port: 0/TCP
State: Running
Started: Thu, 16 Sep 2021 04:51:02 +0000
Ready: True
Restart Count: 0
Environment:
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-plrl6 (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
kube-api-access-plrl6:
Type: Projected (a volume that contains injected data from multiple sources)
TokenExpirationSeconds: 3607
ConfigMapName: kube-root-ca.crt
ConfigMapOptional:
DownwardAPI: true
QoS Class: BestEffort
Node-Selectors:
Tolerations: node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
[centos@ip-172-31-22-14 ~]$ kubectl describe pod namrata-dfb987696-798c7 -n=namtest
Name: namrata-dfb987696-798c7
Namespace: namtest
Priority: 0
Node: ip-172-31-26-110.ap-south-1.compute.internal/172.31.26.110
Start Time: Thu, 16 Sep 2021 06:48:50 +0000
Labels: app=namrata
pod-template-hash=dfb987696
Annotations:
Status: Running
IP: 10.44.0.18
IPs:
IP: 10.44.0.18
Controlled By: ReplicaSet/namrata-dfb987696
Containers:
nginx-devopsschoolv1:
Container ID: docker://72e72132785d747742c832107d43ca13ec0235dab8de2e4390766ed18f6e6ebb
Image: scmgalaxy/nginx-devopsschoolv1
Image ID: docker-pullable://scmgalaxy/nginx-devopsschoolv1@sha256:0544f1e7eb70ee9967819f1655160f5457d47aa24910a32f357c1a41aab3d20b
Port:
Host Port:
State: Running
Started: Thu, 16 Sep 2021 06:49:03 +0000
Ready: True
Restart Count: 0
Environment:
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-qvnfz (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
kube-api-access-qvnfz:
Type: Projected (a volume that contains injected data from multiple sources)
TokenExpirationSeconds: 3607
ConfigMapName: kube-root-ca.crt
ConfigMapOptional:
DownwardAPI: true
QoS Class: BestEffort
Node-Selectors:
Tolerations: node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
Type Reason Age From Message
—- —— —- —- ——-
Normal Scheduled 3m default-scheduler Successfully assigned namtest/namrata-dfb987696-798c7 to ip-172-31-26-110.ap-south-1.compute.internal
Normal Pulling 2m58s kubelet Pulling image “scmgalaxy/nginx-devopsschoolv1”
Normal Pulled 2m48s kubelet Successfully pulled image “scmgalaxy/nginx-devopsschoolv1” in 10.495392305s
Normal Created 2m48s kubelet Created container nginx-devopsschoolv1
Normal Started 2m47s kubelet Started container nginx-devopsschoolv1

Kubernetes

Namrata MU — Wed, 15 Sep 2021 09:39:54 +0000

Kubernetes, also known as K8s, is an open-source system for automating deployment, scaling, and management of containerized applications.

Open source container orchestration tool
It can manage in physical , hybrid and cloud environment
No downtime
High performance and scalability

Benefits of docker-compose

Namrata MU — Wed, 15 Sep 2021 04:44:56 +0000

Docker compose is used for running multiple container as 1 service
Each service is isolated from one another
No dependency to start each service independently
one yaml file contains all and can be run in 1 shot
Docker manages single container , docker-compose manages multiple applications
It is a powerful tool , to set up and deploy application

Start all services: Docker Compose up.
Stop all services: Docker Compose down.
Run Docker Compose file: Docker-compose up -d.
List the entire process: Docker ps.

Docker update & wait

Namrata MU — Tue, 14 Sep 2021 05:13:32 +0000

Update :

[root@ip-172-31-17-58 centos]# docker update –pids-limit 5 6344a718da9b
6344a718da9b
[root@ip-172-31-17-58 centos]# docker update –help
[root@ip-172-31-17-58 centos]# docker update –cpu-period 200 8d2f95364af1
Error response from daemon: CPU cfs period can not be less than 1ms (i.e. 1000) or larger than 1s (i.e. 1000000)
[root@ip-172-31-17-58 centos]# docker update –cpu-period 2000 8d2f95364af1

wait :

[root@ip-172-31-17-58 centos]# docker start 8d2f95364af1
8d2f95364af1
[root@ip-172-31-17-58 centos]# docker stop 8d2f95364af1
8d2f95364af1

In another terminal :

[root@ip-172-31-17-58 centos]# clear
[root@ip-172-31-17-58 centos]# docker wait 8d2f95364af1
0
[root@ip-172-31-17-58 centos]#

Difference between kill /stop , pause/unpause docker

Namrata MU — Mon, 13 Sep 2021 09:23:00 +0000

Kill/stop

Kill -unsafe exit

stop- safe exit

pause/unpause

What is docker and container ?

Namrata MU — Mon, 13 Sep 2021 06:47:19 +0000

What is Docker ?

Answer : Docker helps in containerization of apps , so that app app gets it own environment to run.

What is a container ?

Containers virtualize the operating system unlike VMs. Containers are portable with that it means it can do development and deployment . In terms of docker its also runnable instance of image.

Benefits of Docker ?

Fast to create unlike VMs
Since OS is not contained its light weight
container also contains the required versions of other applications needed for the app
Any number of containers can be spin quickly

Docker Architecture ?

Docker uses client-server architecture . One of the important component is registry . eg app store , jfrog all the registries

Container Lifecycle ?

Create – run -stopped- pause-delete

How docker worker?

Docker images contains all the dependencies needed to run code inside a container. Docker is a container engine basically.