Sujith Rajamohan – Best DevOps https://www.bestdevops.com Lets Learn, Do it & Share! Thats a Best DevOps!!! Fri, 04 Feb 2022 10:25:42 +0000 en-US hourly 1 https://wordpress.org/?v=7.1.3 What are the components of Kubernetes worker and explain each component functions https://www.bestdevops.com/what-are-the-components-of-kubernetes-worker-and-explain-each-component-functions/ Wed, 01 Sep 2021 07:03:44 +0000 https://www.bestdevops.com/?p=20592 <strong>Kubelet</strong> Registers node with cluster Watches apiserver Instantiates pods Reports back to master <strong>Container Engine</strong> Does container management like pulling images, starting/stopping containers <strong>Kube-proxy</strong> Manages kubernetes networking like Pod IP addresses and load balances across all pods in a service ]]> What are the components of Kubernetes Master and explain each component functions https://www.bestdevops.com/what-are-the-components-of-kubernetes-master-and-explain-each-component-functions/ Wed, 01 Sep 2021 06:57:50 +0000 https://www.bestdevops.com/?p=20575 API Server – provides all the operation on cluster using the API.

Control Manager – regulates the state of cluster and performs a task.

Cluster Store – stores the configuration information which can be used by each of the nodes

Scheduler – distributes the workload.

]]> Write down 10 features of Kubernetes https://www.bestdevops.com/write-down-10-features-of-kubernetes/ Wed, 01 Sep 2021 06:51:18 +0000 https://www.bestdevops.com/?p=20534 Service discovery and load balancing Storage orchestration Automated rollouts and rollbacks Automatic bin packing Self-healing Secret and configuration management Horizontal scaling Designed for extensibility

]]> List out number of storage/volume drivers supported by docker https://www.bestdevops.com/list-out-number-of-storage-volume-drivers-supported-by-docker-6/ Tue, 31 Aug 2021 09:43:48 +0000 https://www.bestdevops.com/?p=20442 Overlay2 – preferred storage driver for all currently supported Linux distributions, and requires no extra configuration.

fuse-overlayfs – preferred only for running Rootless Docker on a host that does not provide support for rootless overlay2

btrfs and zfs – The btrfs and zfs storage drivers allow for advanced options, such as creating “snapshots”, but require more maintenance and setup. Each of these relies on the backing filesystem being configured correctly

Vfs –  Intended for testing purposes, and for situations where no copy-on-write filesystem can be used.

Aufs – Preferred storage driver for Docker 18.06 and older, when running on Ubuntu 14.04 on kernel 3.13 which had no support for overlay2.

Devicemapper  – storage driver requires direct-lvm for production environments, because loopback-lvm, while zero-configuration, has very poor performance.

Overlay  – Used for kernels that did not support the “multiple-lowerdir” feature required for overlay2. It is deprecated.

]]> Build all these 5 images and run container and observe the use cases of it https://www.bestdevops.com/build-all-these-5-images-and-run-container-and-observe-the-use-cases-of-it-2/ Tue, 31 Aug 2021 08:47:13 +0000 https://www.bestdevops.com/?p=20419 Docker File 1

	root@ip-172-31-28-155:/home/ubuntu/srm# docker build -f dockerfile1 -t image1 .
	Sending build context to Docker daemon  6.144kB
	Step 1/7 : FROM ubuntu
	 ---> fb52e22af1b0
	Step 2/7 : MAINTAINER Rajesh Kumar << rajesh@scmgalaxy.com>>
	 ---> Using cache
	 ---> 01477b86dfc8
	Step 3/7 : ENV DEBIAN_FRONTEND=noninteractive
	 ---> Using cache
	 ---> 57a1ad7c1cea
	Step 4/7 : RUN apt-get update
	 ---> Using cache
	 ---> 1207d5f945f3
	Step 5/7 : RUN apt-get -y install tzdata
	 ---> Using cache
	 ---> e99c418f5399
	Step 6/7 : RUN apt-get update && apt-get install git -y && apt-get install -yq apache2
	 ---> Using cache
	 ---> 0adfc67f9737
	Step 7/7 : CMD /usr/sbin/apache2ctl -D FOREGROUND
	 ---> Using cache
	 ---> f5b4a10dc064
	Successfully built f5b4a10dc064
	Successfully tagged image1:latest

	root@ip-172-31-28-155:/home/ubuntu/srm# docker run -it image1

Docker File 2

	root@ip-172-31-28-155:/home/ubuntu/srm# docker build -f dockerfile2 -t image2 .
	Sending build context to Docker daemon  6.144kB
	Step 1/7 : FROM ubuntu
	 ---> fb52e22af1b0
	Step 2/7 : MAINTAINER Rajesh Kumar << rajesh@scmgalaxy.com>>
	 ---> Using cache
	 ---> 01477b86dfc8
	Step 3/7 : ENV DEBIAN_FRONTEND=noninteractive
	 ---> Using cache
	 ---> 57a1ad7c1cea
	Step 4/7 : RUN apt-get update
	 ---> Using cache
	 ---> 1207d5f945f3
	Step 5/7 : RUN apt-get -y install tzdata
	 ---> Using cache
	 ---> e99c418f5399
	Step 6/7 : RUN apt-get update && apt-get install git -y && apt-get install -yq apache2
	 ---> Using cache
	 ---> 0adfc67f9737
	Step 7/7 : CMD echo "Hello world"
	 ---> Using cache
	 ---> f3008cf52e3f
	Successfully built f3008cf52e3f
	Successfully tagged image2:latest
	
	root@ip-172-31-28-155:/home/ubuntu/srm# docker run -it image2
	Hello world

Docker File 3

	root@ip-172-31-28-155:/home/ubuntu/srm# docker build -f dockerfile3 -t image3 .               Sending build context to Docker daemon  7.168kB
	Step 1/8 : FROM ubuntu
	 ---> fb52e22af1b0
	Step 2/8 : MAINTAINER Rajesh Kumar << rajesh@scmgalaxy.com>>
	 ---> Using cache
	 ---> 01477b86dfc8
	Step 3/8 : ENV DEBIAN_FRONTEND=noninteractive
	 ---> Using cache
	 ---> 57a1ad7c1cea
	Step 4/8 : RUN apt-get update
	 ---> Using cache
	 ---> 1207d5f945f3
	Step 5/8 : RUN apt-get update
	 ---> Using cache
	 ---> 4156a194a23b
	Step 6/8 : RUN apt-get -y install tzdata
	 ---> Using cache
	 ---> 9b31137fbd43
	Step 7/8 : RUN apt-get update && apt-get install git -y && apt-get install -yq apache2
	 ---> Using cache
	 ---> 17c90bab3df8
	Step 8/8 : ENTRYPOINT ["/bin/echo", "Hello"]
	 ---> Using cache
	 ---> faf040ddabad
	Successfully built faf040ddabad
	
	root@ip-172-31-28-155:/home/ubuntu/srm# docker run -it image3
	Hello

Docker File 4

	root@ip-172-31-28-155:/home/ubuntu/srm# docker build -f dockerfile4 -t image4 .
	Sending build context to Docker daemon  7.168kB
	Step 1/8 : FROM ubuntu
	 ---> fb52e22af1b0
	Step 2/8 : MAINTAINER Rajesh Kumar << rajesh@scmgalaxy.com>>
	 ---> Using cache
	 ---> 01477b86dfc8
	Step 3/8 : ENV DEBIAN_FRONTEND=noninteractive
	 ---> Using cache
	 ---> 57a1ad7c1cea
	Step 4/8 : RUN apt-get update
	 ---> Using cache
	 ---> 1207d5f945f3
	Step 5/8 : RUN apt-get -y install tzdata
	 ---> Using cache
	 ---> e99c418f5399
	Step 6/8 : RUN apt-get update && apt-get install git -y && apt-get install -yq apache2
	 ---> Using cache
	 ---> 0adfc67f9737
	Step 7/8 : EXPOSE 80
	 ---> Using cache
	 ---> d984750330b2
	Step 8/8 : CMD /usr/sbin/apache2ctl -D FOREGROUND
	 ---> Using cache
	 ---> ef7c01cfe904
	Successfully built ef7c01cfe904
	Successfully tagged image4:latest
	
	root@ip-172-31-28-155:/home/ubuntu/srm# docker run -it image4

Apache default page exposed to port 80

Docker File 5

	root@ip-172-31-28-155:/home/ubuntu/srm# docker build -f dockerfile5 -t image5 .               Sending build context to Docker daemon  7.168kB
	Step 1/8 : FROM ubuntu
	 ---> fb52e22af1b0
	Step 2/8 : MAINTAINER Rajesh Kumar << rajesh@scmgalaxy.com>>
	 ---> Using cache
	 ---> 01477b86dfc8
	Step 3/8 : ENV DEBIAN_FRONTEND=noninteractive
	 ---> Using cache
	 ---> 57a1ad7c1cea
	Step 4/8 : RUN apt-get update
	 ---> Using cache
	 ---> 1207d5f945f3
	Step 5/8 : RUN apt-get -y install tzdata
	 ---> Using cache
	 ---> e99c418f5399
	Step 6/8 : RUN apt-get install git -y && apt-get install -yq apache2
	 ---> Using cache
	 ---> a10251de0aa1
	Step 7/8 : CMD echo "Hello world"
	 ---> Using cache
	 ---> da7318408c65
	Step 8/8 : ENTRYPOINT ["/bin/echo", "Hello"]
	 ---> Using cache
	 ---> 95fd2176a9d8
	Successfully built 95fd2176a9d8
	Successfully tagged image5:latest
	
	root@ip-172-31-28-155:/home/ubuntu/srm# docker run -it image5
	Hello /bin/sh -c echo "Hello world"
]]> Write an example dockerfile with 2 CMD, 2 ENTRYPOINT and 1 CMD/1 ENTRYPOINT and write down behavior of it. https://www.bestdevops.com/write-an-example-dockerfile-with-2-cmd-2-entrypoint-and-1-cmd-1-entrypoint-and-write-down-behavior-of-it/ Tue, 31 Aug 2021 08:10:31 +0000 https://www.bestdevops.com/?p=20384 root@ip-172-31-28-155:/home/ubuntu/srm# cat dockerfile_multi FROM ubuntu MAINTAINER Rajesh Kumar << rajesh@scmgalaxy.com>> ENV DEBIAN_FRONTEND=noninteractive RUN apt-get update RUN apt-get -y install tzdata RUN apt-get install git -y && apt-get install -yq apache2 CMD echo "Hello CMD 1" ENTRYPOINT ["/bin/echo", "Hello Entry 1"] <strong>root@ip-172-31-28-155:/home/ubuntu/srm# docker run -it image_multi Hello Entry 1 /bin/sh -c echo "Hello CMD 1"</strong> root@ip-172-31-28-155:/home/ubuntu/srm# cat dockerfile_multi FROM ubuntu MAINTAINER Rajesh Kumar << rajesh@scmgalaxy.com>> ENV DEBIAN_FRONTEND=noninteractive RUN apt-get update RUN apt-get -y install tzdata RUN apt-get install git -y && apt-get install -yq apache2 CMD echo "Hello CMD 1" CMD echo "Hello CMD 2" <strong>root@ip-172-31-28-155:/home/ubuntu/srm# docker run -it image_multi Hello CMD 2</strong> root@ip-172-31-28-155:/home/ubuntu/srm# cat dockerfile_multi FROM ubuntu MAINTAINER Rajesh Kumar << rajesh@scmgalaxy.com>> ENV DEBIAN_FRONTEND=noninteractive RUN apt-get update RUN apt-get -y install tzdata RUN apt-get install git -y && apt-get install -yq apache2 ENTRYPOINT ["/bin/echo", "Hello Entry 1"] ENTRYPOINT ["/bin/echo", "Hello Entry 2"] <strong>root@ip-172-31-28-155:/home/ubuntu/srm# docker run -it image_multi Hello Entry 2</strong>
]]> Create one image which have base as ubuntu and with git, ntp, apache2 https://www.bestdevops.com/create-one-image-which-have-base-as-ubuntu-and-with-git-ntp-apache2-7/ Tue, 31 Aug 2021 05:51:02 +0000 https://www.bestdevops.com/?p=20330 root@ip-172-31-28-155:/home/ubuntu# docker run -itd ubuntu root@ip-172-31-28-155:/home/ubuntu# docker attach 1e1fe360cf47 [root@1e1fe360cf47 /]# apt-get update [root@1e1fe360cf47 /]# apt-get install git [root@1e1fe360cf47 /]# apt-get install ntp [root@1e1fe360cf47 /]# apt-get install apache2 root@ip-172-31-28-155:/home/ubuntu# docker commit -a"sujith" -m"ubuntu_git" 1e1fe360cf47 srm-ubuntu root@ip-172-31-28-155:/home/ubuntu# docker images REPOSITORY TAG IMAGE ID CREATED SIZE manunar1 latest ba3b4bb2ee4f 4 seconds ago 611MB srm-ubuntu latest 55edd4725739 42 seconds ago 259MB ub-up-git-ap2 latest 3227855a10e9 3 minutes ago 259MB root@ip-172-31-28-155:/home/ubuntu# docker history ubuntu IMAGE CREATED CREATED BY SIZE COMMENT fb52e22af1b0 4 hours ago /bin/sh -c #(nop) CMD ["bash"] 0B <missing> 4 hours ago /bin/sh -c #(nop) ADD file:d2abf27fe2e8b0b5f… 72.8MB root@ip-172-31-28-155:/home/ubuntu# docker history srm-ubuntu IMAGE CREATED CREATED BY SIZE COMMENT 55edd4725739 About a minute ago bash 187MB ubuntu_git fb52e22af1b0 4 hours ago /bin/sh -c #(nop) CMD ["bash"] 0B <missing> 4 hours ago /bin/sh -c #(nop) ADD file:d2abf27fe2e8b0b5f… 72.8MB root@ip-172-31-28-155:/home/ubuntu# docker run -itd srm-ubuntu c01f05cfa01cdc7c8485c60325e6734ed79200869fdafaa8b195490c0e17e85c root@ip-172-31-28-155:/home/ubuntu# docker attach c01f05cfa01cdc7c8485c60325e6734ed79200869fdafaa8b195490c0e17e85c]]> Create one image which have base as centos and with git, ntp, httpd https://www.bestdevops.com/create-one-image-which-have-base-as-centos-and-with-git-ntp-httpd-5/ Tue, 31 Aug 2021 05:47:16 +0000 https://www.bestdevops.com/?p=20317 root@ip-172-31-28-155:/home/ubuntu# docker run -itd centos root@ip-172-31-28-155:/home/ubuntu# docker attach 6b75851431b4 [root@6b75851431b4 /]# yum install epel-release [root@6b75851431b4 /]# yum install ntp [root@6b75851431b4 /]# yum install httpd root@ip-172-31-28-155:/home/ubuntu# docker commit -a"sujith" -m"centos_git" 6b75851431b4 srm-centos sha256:d3afd249fdd0902cb87aa3ab9f2f7710014190d730d4bd7ceca5527e4e75cdd6 root@ip-172-31-28-155:/home/ubuntu# docker run -itd srm-centos e08aa7826a7c9798caf23d5f461ab2ed022978e67ac25ec7d7f97e90f7a44d40

]]> What is Storage Driver and types of storage driver ? https://www.bestdevops.com/what-is-storage-driver-and-types-of-storage-driver-3/ Tue, 31 Aug 2021 05:42:22 +0000 https://www.bestdevops.com/?p=20313 Storage Driver is used to store and manage images and containers on Docker host.

Types of Storage Drivers

aufs
btrfs
devicemapper
vfs
zfs
root@ip-172-31-28-155:/home/ubuntu# docker info
Storage Driver: overlay2
  Backing Filesystem: extfs
  Supports d_type: true
  Native Overlay Diff: true
  userxattr: false
]]> What is the diff docker pause and docker unpause ? https://www.bestdevops.com/what-is-the-diff-docker-pause-and-docker-unpause/ Mon, 30 Aug 2021 07:44:50 +0000 https://www.bestdevops.com/?p=20030 Pause command suspends all process in the container while unpause command un-suspends all process.

	root@ip-172-31-28-155:/home/ubuntu# docker pause srm
	srm
	root@ip-172-31-28-155:/home/ubuntu# docker ps
	CONTAINER ID   IMAGE     COMMAND              CREATED              STATUS                  PORTS     NAMES
	05d0bb37cd21   httpd     "httpd-foreground"   About a minute ago   Up 9 seconds (Paused)   80/tcp    srm
	
	root@ip-172-31-28-155:/home/ubuntu# docker unpause srm
	srm
	root@ip-172-31-28-155:/home/ubuntu# docker ps
	CONTAINER ID   IMAGE     COMMAND              CREATED          STATUS              PORTS     NAMES
	05d0bb37cd21   httpd     "httpd-foreground"   2 minutes ago    Up 53 seconds       80/tcp    srm
]]> What is the diff between docker stop and docker kill? https://www.bestdevops.com/what-is-the-diff-between-docker-stop-and-docker-kill/ Mon, 30 Aug 2021 07:43:28 +0000 https://www.bestdevops.com/?p=19989 Docker stop command exits the container with exit code 0 while docker kill command exit the container with exit code 137.

root@ip-172-31-28-155:/home/ubuntu# docker stop srm
root@ip-172-31-28-155:/home/ubuntu# docker ps -a | grep srm
05d0bb37cd21   httpd          "httpd-foreground"       4 minutes ago    Exited (0) 26 seconds ago               srm

root@ip-172-31-28-155:/home/ubuntu# docker start srm
root@ip-172-31-28-155:/home/ubuntu# docker kill srm
root@ip-172-31-28-155:/home/ubuntu# docker ps -a | grep srm
	05d0bb37cd21   httpd          "httpd-foreground"       5 minutes ago    Exited (137) 2 seconds ago                  srm
]]> Assignment for docker day 1 https://www.bestdevops.com/assignment-for-docker-day-1-8/ Mon, 30 Aug 2021 07:33:19 +0000 https://www.bestdevops.com/?p=19846 Q1. Explain what is Docker Container with image?

  1. Light weight mechanism of isolating running process defined by specific images with resources like root filesystem, user and network.

]]>