THE ADMIN's LAB : DOCKER-2 (INSTALL & BEGIN)

DOCKER-2 (INSTALL & BEGIN)

Now we need to install docker,

Below are the pre installation considerations,

1. Swap should be off

2. Internet access

3. Few rpm’s

I am working with CentOS 7.9

[root@centos7-i2 ~]# swapoff –a

[root@centos7-i2 ~]# vi /etc/fstab

# /etc/fstab

# Created by anaconda on Sat Feb 20 17:12:32 2021

# Accessible filesystems, by reference, are maintained under '/dev/disk'

# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info

/dev/mapper/centos-root / xfs defaults 0 0

UUID=e7b57144-0ce9-47e7-8366-accb226788c0 /boot xfs defaults 0 0

#/dev/mapper/centos-swap swap swap defaults 0 0

Comment the swap partition

Disable Network manager (Optional)

# systemctl stop NetworkManager;systemctl disable NetworkManager

Removed symlink /etc/systemd/system/multi-user.target.wants/NetworkManager.service.

Removed symlink /etc/systemd/system/dbus-org.freedesktop.nm-dispatcher.service.

Removed symlink /etc/systemd/system/network-online.target.wants/NetworkManager-wait-online.service.

Enable Internet,

# vi /etc/resolv.conf

nameserver 192.168.137.1

nameserver 8.8.8.8

nameserver 8.8.4.4

# vi /etc/sysconfig/network-scripts/ifcfg-ens33

#add below at end

DNS1="192.168.137.1"

DNS2="8.8.8.8"

DNS3="8.8.4.4"

Now mount the CentOS DVD to install required RPM’s.

# mkdir -p /mnt/disc

# mount /dev/sr0 /mnt/disc

# vi /etc/yum.repos.d/CentOS-Media.repo

[InstallMedia]

name=DVD for CentOS7

gpgcheck=0

enabled=1

baseurl=file:///mnt/disc/

# yum clean all;yum repolist enabled;yum update

Yum update will take time and approx 1.1GB of data,

[root@centos-docker1 ~]# yum install -y yum-utils device-mapper-persistent-data lvm2

Remove all previous instances,

# yum remove docker \

docker-client \

docker-client-latest \

docker-common \

docker-latest \

docker-latest-logrotate \

docker-logrotate \

docker-engine

# yum install -y yum-utils

Now we can proceed for docker installation, need to configure yum repo to direct install from internet

# yum-config-manager \

--add-repo \

https://download.docker.com/linux/centos/docker-ce.repo

*** If you completed yum update on CentOS 7.9 then directly jump to “yum install docker-ce docker-ce-cli”

=========================================

If some required packages missing then below will help

=========================================

[root@centos7-i2 ~]# yum install https://download.docker.com/linux/centos/7/x86_64/stable/Packages/containerd.io-1.2.6-3.3.el7.x86_64.rpm

https://centos.pkgs.org/7/centos-extras-x86_64/

Binary Package

http://mirror.centos.org/centos/7/extras/x86_64/Packages/slirp4netns-0.4.3-4.el7_8.x86_64.rpm

# yum install https://vault.centos.org/centos/7.8.2003/extras/x86_64/Packages/container-selinux-2.107-1.el7_6.noarch.rpm

# yum install http://mirror.centos.org/centos/7/extras/x86_64/Packages/slirp4netns-0.4.3-4.el7_8.x86_64.rpm

# yum install http://mirror.centos.org/centos/7/extras/x86_64/Packages/fuse3-libs-3.6.1-4.el7.x86_64.rpm

# yum install http://mirror.centos.org/centos/7/extras/x86_64/Packages/fuse-overlayfs-0.7.2-6.el7_8.x86_64.rpm

# yum install https://download.docker.com/linux/centos/7/x86_64/stable/Packages/containerd.io-1.2.6-3.3.el7.x86_64.rpm

========================================================

Continue ………

# yum install docker-ce docker-ce-cli

Loaded plugins: fastestmirror, langpacks

docker-ce-stable | 3.5 kB 00:00

(1/2): docker-ce-stable/7/x86_64/updateinfo | 55 B 00:00

(2/2): docker-ce-stable/7/x86_64/primary_db | 70 kB 00:00

Loading mirror speeds from cached hostfile

* base: centos.mirrors.estointernet.in

* extras: centos.mirrors.estointernet.in

* updates: centos.mirrors.estointernet.in

Resolving Dependencies

--> Running transaction check

---> Package docker-ce.x86_64 3:20.10.12-3.el7 will be installed

--> Processing Dependency: container-selinux >= 2:2.74 for package: 3:docker-ce- 20.10.12-3.el7.x86_64

====================O/P Truncated=======================

setools-libs x86_64 3.3.8-4.el7 base 620 k

systemd x86_64 219-78.el7_9.5 updates 5.1 M

systemd-libs x86_64 219-78.el7_9.5 updates 419 k

systemd-python x86_64 219-78.el7_9.5 updates 146 k

systemd-sysv x86_64 219-78.el7_9.5 updates 97 k

Transaction Summary

================================================================================

Install 2 Packages (+ 8 Dependent packages)

Upgrade 3 Packages (+24 Dependent packages)

Total download size: 114 M

Is this ok [y/d/N]: y

====================O/P Truncated=======================

(35/37): systemd-219-78.el7_9.5.x86_64.rpm | 5.1 MB 00:00:04

(36/37): glib2-2.56.1-9.el7_9.x86_64.rpm | 2.5 MB 00:00:08

(37/37): selinux-policy-targeted-3.13.1-268.el7_9.2.noarch.rpm | 7.0 MB 00:00:07

--------------------------------------------------------------------------------------------------------------------------------------

Total 2.9 MB/s | 114 MB 00:00:39

Retrieving key from https://download.docker.com/linux/centos/gpg

Importing GPG key 0x621E9F35:

Userid : "Docker Release (CE rpm) <docker@docker.com>"

Fingerprint: 060a 61c5 1b55 8a7f 742b 77aa c52f eb6b 621e 9f35

From : https://download.docker.com/linux/centos/gpg

Is this ok [y/N]: y

====================O/P Truncated=======================

Installed:

docker-ce.x86_64 3:20.10.12-3.el7 docker-ce-cli.x86_64 1:20.10.12-3.el7

Dependency Installed:

container-selinux.noarch 2:2.119.2-1.911c772.el7_8 containerd.io.x86_64 0:1.4.12-3.1.el7

docker-ce-rootless-extras.x86_64 0:20.10.12-3.el7 docker-scan-plugin.x86_64 0:0.12.0-3.el7

fuse-overlayfs.x86_64 0:0.7.2-6.el7_8 fuse3-libs.x86_64 0:3.6.1-4.el7

lz4.x86_64 0:1.8.3-1.el7 slirp4netns.x86_64 0:0.4.3-4.el7_8

Updated:

centos-release.x86_64 0:7-9.2009.1.el7.centos dracut.x86_64 0:033-572.el7 initscripts.x86_64 0:9.49.53-1.el7_9.1

Dependency Updated:

cryptsetup.x86_64 0:2.0.3-6.el7 cryptsetup-libs.x86_64 0:2.0.3-6.el7

cryptsetup-python.x86_64 0:2.0.3-6.el7 dracut-config-rescue.x86_64 0:033-572.el7

dracut-network.x86_64 0:033-572.el7 glib2.x86_64 0:2.56.1-9.el7_9

kmod.x86_64 0:20-28.el7 libgudev1.x86_64 0:219-78.el7_9.5

libseccomp.x86_64 0:2.3.1-4.el7 libselinux.x86_64 0:2.5-15.el7

libselinux-python.x86_64 0:2.5-15.el7 libselinux-utils.x86_64 0:2.5-15.el7

libsemanage.x86_64 0:2.5-14.el7 libsemanage-python.x86_64 0:2.5-14.el7

libsepol.x86_64 0:2.5-10.el7 policycoreutils.x86_64 0:2.5-34.el7

policycoreutils-python.x86_64 0:2.5-34.el7 selinux-policy.noarch 0:3.13.1-268.el7_9.2

selinux-policy-targeted.noarch 0:3.13.1-268.el7_9.2 setools-libs.x86_64 0:3.3.8-4.el7

systemd.x86_64 0:219-78.el7_9.5 systemd-libs.x86_64 0:219-78.el7_9.5

systemd-python.x86_64 0:219-78.el7_9.5 systemd-sysv.x86_64 0:219-78.el7_9.5

Complete!

# systemctl start docker;systemctl status docker

Job for docker.service failed because the control process exited with error code. See "systemctl status docker.service" and "journalctl -xe" for details.

● docker.service - Docker Application Container Engine

Loaded: loaded (/usr/lib/systemd/system/docker.service; disabled; vendor preset: disabled)

Active: activating (auto-restart) (Result: exit-code) since Sun 2022-01-23 16:15:21 IST; 82ms ago

Docs: https://docs.docker.com

Process: 17663 ExecStart=/usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock (code=exited, status=1/FAILURE)

Main PID: 17663 (code=exited, status=1/FAILURE)

Jan 23 16:15:21 centos7-i2 systemd[1]: Unit docker.service entered failed state.

Jan 23 16:15:21 centos7-i2 systemd[1]: docker.service failed.

[root@centos7-i2 ~]# systemctl enable docker

Created symlink from /etc/systemd/system/multi-user.target.wants/docker.service to /usr/lib/systemd/system/docker.service.

[root@centos7-i2 ~]# systemctl start docker;systemctl status docker

Job for docker.service failed because the control process exited with error code. See "systemctl status docker.service" and "journalctl -xe" for details.

● docker.service - Docker Application Container Engine

Loaded: loaded (/usr/lib/systemd/system/docker.service; enabled; vendor preset: disabled)

Active: activating (auto-restart) (Result: exit-code) since Sun 2022-01-23 16:16:34 IST; 78ms ago

Docs: https://docs.docker.com

Process: 17970 ExecStart=/usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock (code=exited, status=1/FAILURE)

Main PID: 17970 (code=exited, status=1/FAILURE)

Jan 23 16:16:34 centos7-i2 systemd[1]: docker.service: main process exited, code=exited, status=1/FAILURE

Jan 23 16:16:34 centos7-i2 systemd[1]: Failed to start Docker Application Container Engine.

Jan 23 16:16:34 centos7-i2 systemd[1]: Unit docker.service entered failed state.

Jan 23 16:16:34 centos7-i2 systemd[1]: docker.service failed.

[root@centos7-i2 ~]# service docker restart

Redirecting to /bin/systemctl restart docker.service

Job for docker.service failed because the control process exited with error code. See "systemctl status docker.service" and "journalctl -xe" for details.

[root@centos7-i2 ~]# journalctl -xe

Jan 23 16:18:13 centos7-i2 dockerd[18361]: time="2022-01-23T16:18:13.357693743+05:30" level=info msg="Loading containers: start."

Jan 23 16:18:13 centos7-i2 firewalld[888]: 2022-01-23 16:18:13 ERROR: INVALID_TYPE: structure size mismatch 16 != 13

Jan 23 16:18:13 centos7-i2 firewalld[888]: 2022-01-23 16:18:13 ERROR: COMMAND_FAILED: '/sbin/iptables -t filter -C FORWARD -j DOCKER-I

Jan 23 16:18:14 centos7-i2 dockerd[18361]: time="2022-01-23T16:18:14.338675640+05:30" level=info msg="Default bridge (docker0) is assi

Jan 23 16:18:14 centos7-i2 firewalld[888]: 2022-01-23 16:18:14 ERROR: COMMAND_FAILED: '/sbin/iptables -t nat -C DOCKER -i docker0 -j R

Jan 23 16:18:14 centos7-i2 firewalld[888]: 2022-01-23 16:18:14 ERROR: COMMAND_FAILED: '/sbin/iptables -D FORWARD -i docker0 -o docker0

Jan 23 16:18:14 centos7-i2 firewalld[888]: 2022-01-23 16:18:14 ERROR: INVALID_ZONE: docker

Jan 23 16:18:14 centos7-i2 dockerd[18361]: time="2022-01-23T16:18:14.552234846+05:30" level=warning msg="unmountAndDeactivate: open /v

Jan 23 16:18:14 centos7-i2 dockerd[18361]: time="2022-01-23T16:18:14.626043607+05:30" level=error msg="Failed to get event" error="rpc

Jan 23 16:18:14 centos7-i2 dockerd[18361]: time="2022-01-23T16:18:14.626383098+05:30" level=info msg="Waiting for containerd to be rea

Jan 23 16:18:14 centos7-i2 dockerd[18361]: time="2022-01-23T16:18:14.631182235+05:30" level=warning msg="Error while testing if contai

Jan 23 16:18:14 centos7-i2 dockerd[18361]: failed to start daemon: Error initializing network controller: Error creating default "brid

Jan 23 16:18:14 centos7-i2 systemd[1]: docker.service: main process exited, code=exited, status=1/FAILURE

Jan 23 16:18:14 centos7-i2 systemd[1]: Failed to start Docker Application Container Engine.

-- Subject: Unit docker.service has failed

-- Defined-By: systemd

-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel

-- Unit docker.service has failed.

-- The result is failed.

Jan 23 16:18:14 centos7-i2 systemd[1]: Unit docker.service entered failed state.

Jan 23 16:18:14 centos7-i2 systemd[1]: docker.service failed.

Seems something is preventing docker to start,

Need to check below

1. Swap

2. Firewall

3. SELinux

[root@centos7-i2 ~]# cat /etc/fstab |grep -i swap

#/dev/mapper/centos-swap swap swap defaults 0 0

[root@centos7-i2 ~]# systemctl stop firewalld

[root@centos7-i2 ~]# systemctl disable firewalld

Removed symlink /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.

Removed symlink /etc/systemd/system/basic.target.wants/firewalld.service.

[root@centos7-i2 ~]# sudo sed -i 's/^SELINUX=enforcing$/SELINUX=permissive/' /etc/selinux/config

[root@centos7-i2 ~]# systemctl start docker;systemctl status docker

● docker.service - Docker Application Container Engine

Loaded: loaded (/usr/lib/systemd/system/docker.service; enabled; vendor preset: disabled)

Active: active (running) since Sun 2022-01-23 16:24:14 IST; 51ms ago

Docs: https://docs.docker.com

Main PID: 47681 (dockerd)

Memory: 36.7M

CGroup: /system.slice/docker.service

└─47681 /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock

[root@centos7-i2 ~]# docker version

Client: Docker Engine - Community

Version: 20.10.12

API version: 1.41

Go version: go1.16.12

Git commit: e91ed57

Built: Mon Dec 13 11:45:41 2021

OS/Arch: linux/amd64

Context: default

Experimental: true

Server: Docker Engine - Community

Engine:

Version: 20.10.12

API version: 1.41 (minimum version 1.12)

Go version: go1.16.12

Git commit: 459d0df

Built: Mon Dec 13 11:44:05 2021

OS/Arch: linux/amd64

Experimental: false

containerd:

Version: 1.4.12

GitCommit: 7b11cfaabd73bb80907dd23182b9347b4245eb5d

runc:

Version: 1.0.2

GitCommit: v1.0.2-0-g52b36a2

docker-init:

Version: 0.19.0

GitCommit: de40ad0

List available docker commands,

[root@centos7-i2 ~]# docker

Usage: docker [OPTIONS] COMMAND

A self-sufficient runtime for containers

Options:

--config string Location of client config files (default "/root/.docker")

-c, --context string Name of the context to use to connect to the daemon (overrides DOCKER_HOST env var and

default context set with "docker context use")

-D, --debug Enable debug mode

-H, --host list Daemon socket(s) to connect to

-l, --log-level string Set the logging level ("debug"|"info"|"warn"|"error"|"fatal") (default "info")

--tls Use TLS; implied by --tlsverify

--tlscacert string Trust certs signed only by this CA (default "/root/.docker/ca.pem")

--tlscert string Path to TLS certificate file (default "/root/.docker/cert.pem")

--tlskey string Path to TLS key file (default "/root/.docker/key.pem")

--tlsverify Use TLS and verify the remote

-v, --version Print version information and quit

Management Commands:

app* Docker App (Docker Inc., v0.9.1-beta3)

builder Manage builds

buildx* Build with BuildKit (Docker Inc., v0.6.3-docker)

config Manage Docker configs

container Manage containers

context Manage contexts

image Manage images

manifest Manage Docker image manifests and manifest lists

network Manage networks

node Manage Swarm nodes

plugin Manage plugins

scan* Docker Scan (Docker Inc., v0.8.0)

secret Manage Docker secrets

service Manage services

stack Manage Docker stacks

swarm Manage Swarm

system Manage Docker

trust Manage trust on Docker images

volume Manage volumes

Commands:

attach Attach local standard input, output, and error streams to a running container

build Build an image from a Dockerfile

commit Create a new image from a container's changes

cp Copy files/folders between a container and the local filesystem

create Create a new container

diff Inspect changes to files or directories on a container's filesystem

events Get real time events from the server

exec Run a command in a running container

export Export a container's filesystem as a tar archive

history Show the history of an image

images List images

import Import the contents from a tarball to create a filesystem image

info Display system-wide information

inspect Return low-level information on Docker objects

kill Kill one or more running containers

load Load an image from a tar archive or STDIN

logout Log out from a Docker registry

logs Fetch the logs of a container

pause Pause all processes within one or more containers

port List port mappings or a specific mapping for the container

ps List containers

pull Pull an image or a repository from a registry

push Push an image or a repository to a registry

rename Rename a container

restart Restart one or more containers

rm Remove one or more containers

rmi Remove one or more images

run Run a command in a new container

save Save one or more images to a tar archive (streamed to STDOUT by default)

search Search the Docker Hub for images

start Start one or more stopped containers

stats Display a live stream of container(s) resource usage statistics

stop Stop one or more running containers

tag Create a tag TARGET_IMAGE that refers to SOURCE_IMAGE

top Display the running processes of a container

unpause Unpause all processes within one or more containers

update Update configuration of one or more containers

version Show the Docker version information

wait Block until one or more containers stop, then print their exit codes

Run 'docker COMMAND --help' for more information on a command.

To get more help with docker, check out our guides at https://docs.docker.com/go/guides/

Searching desired container,

[root@centos7-i2 ~]# docker search nginx

[root@centos7-i2 ~]# docker search centos

Installation of desired container,

[root@centos7-i2 ~]# docker run ubuntu

Unable to find image 'ubuntu:latest' locally

latest: Pulling from library/ubuntu

f3ef4ff62e0d: Pull complete

Digest: sha256:a0d9e826ab87bd665cfc640598a871b748b4b70a01a4f3d174d4fb02adad07a9

Status: Downloaded newer image for ubuntu:latest

WARNING: IPv4 forwarding is disabled. Networking will not work.

[root@centos7-i2 ~]# vi /etc/sysctl.conf

# sysctl settings are defined through files in

# /usr/lib/sysctl.d/, /run/sysctl.d/, and /etc/sysctl.d/.

# Vendors settings live in /usr/lib/sysctl.d/.

# To override a whole file, create a new file with the same in

# /etc/sysctl.d/ and put new settings there. To override

# only specific settings, add a file with a lexically later

# name in /etc/sysctl.d/ and put new settings there.

# For more information, see sysctl.conf(5) and sysctl.d(5).

net.ipv4.ip_forward=1 # add this line

[root@centos7-i2 ~]# systemctl restart network

[root@centos7-i2 ~]# sysctl net.ipv4.ip_forward

net.ipv4.ip_forward = 1

Check the running docker containers,

[root@centos7-i2 ~]# docker ps

CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES

Check all docker containers,

[root@centos7-i2 ~]# docker ps -a

CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES

fdd1dd0482c0 ubuntu "bash" 2 minutes ago Exited (0) 2 minutes ago competent_varahamihira

8eeaf46c3b96 hello-world "/hello" 23 hours ago Exited (0) 23 hours ago fervent_meninsky

Remove the running docker containers,

[root@centos7-i2 ~]# docker rm fdd1dd0482c0

fdd1dd0482c0

[root@centos7-i2 ~]# docker ps -a

CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES

8eeaf46c3b96 hello-world "/hello" 23 hours ago Exited (0) 23 hours ago fervent_meninsky

[root@centos7-i2 ~]# docker run ubuntu

[root@centos7-i2 ~]# docker ps -a

CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES

4fdd2745b16f ubuntu "bash" 32 seconds ago Exited (0) 30 seconds ago heuristic_ellis

8eeaf46c3b96 hello-world "/hello" 23 hours ago Exited (0) 23 hours ago fervent_meninsky

THE ADMIN's LAB

Sunday 23 January 2022

DOCKER-2 (INSTALL & BEGIN)

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