Setup CentOS 8 and Docker

Collection of commands required to setup CentOS development environment

Installing Ntfs Support

Command to enable NTFS/FAT32 file systems support:

sudo dnf install epel-release -y
sudo dnf install ntfs-3g -y

Installing OpenJDK

sudo dnf install java-1.8.0-openjdk-devel
sudo dnf install java-11-openjdk-devel

Installing Git

sudo dnf install git
https://help.github.com/en/enterprise/2.16/user/authenticating-to-github/generating-a-new-ssh-key-and-adding-it-to-the-ssh-agent
vim ~/.ssh/config
and paste and save the following content:
```
Host github.com
Hostname ssh.github.com
Port 443
```
chmod 600 ~/.ssh/config

Installing Docker CE

By default podman-docker is installed. and this will cause the following error:

package docker-ce-cli-1:19.03.5-3.el7.x86_64 conflicts with docker provided by podman-docker-1.0.5-1.gitf604175.module_el8.0.0+194+ac560166.noarch

To avoid this issue run the following commands:

sudo dnf remove -y docker docker-client docker-client-latest docker-common docker-latest docker-latest-logrotate docker-logrotate docker-selinux docker-engine-selinux docker-engine
sudo dnf -y install dnf-plugins-core
sudo dnf config-manager --add-repo=https://download.docker.com/linux/centos/docker-ce.repo
sudo dnf -y install https://download.docker.com/linux/centos/7/x86_64/stable/Packages/containerd.io-1.2.6-3.3.el7.x86_64.rpm
sudo dnf install docker-ce docker-ce-cli containerd.io
sudo dnf clean packages
sudo dnf list docker-ce
sudo systemctl start docker
sudo systemctl enable docker

Test Docker CE

docker --version
docker run hello-world
sudo docker run hello-world
docker run -it ubuntu bash
sudo docker run -it ubuntu bash

Installing Docker Compose

sudo curl -L "https://github.com/docker/compose/releases/download/1.25.1/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose
sudo chmod +x /usr/local/bin/docker-compose
sudo usermod -aG docker $USER
docker-compose --version
docker stats
docker version

Troubleshooting

408 Request Time-out while signing in or pulling an image

This issue was caused by the fact that the MTU on both the ethernet and wifi connection was set to AUTO. The issue can be fixed changing the MTU to 900 using one of the following options:

For each network interface managed by the NetworkManager daemon, a configuration file is created inside the /etc/sysconfig/network-scripts directory. The name of the file is composed by the ifcfg- prefix plus the name of the interface.

We can manually change the NIC configuration files:

sudo vim /etc/sysconfig/network-scripts/ifcfg-[NIC_NAME]
sudo nmcli connection down [NIC_NAME] 
sudo nmcli connection up [NIC_NAME]

By running the ip addr command again we can verify the IP has changed:

ip addr | grep [NIC_NAME]

using nmtui:

sudo nmtui
sudo nmcli connection down [NIC_NAME] 
sudo nmcli connection up [NIC_NAME]

Usingip link set

ip link list
sudo ip link set wlp2s0 mtu 900
sudo ip link set enp0s31f6 mtu 900
sudo systemctl restart NetworkManager

Container B has not access to Container A and log file error is:

NO ROUTE TO HOST network request from container to...

This was firewall issue in the OS hosting docker. To troubleshoot the issue: 1) Check if the port from container A is accessible from the localhost:

ss | head -1 1.ss -l | grep LISTEN | grep tcp
telnet localhost 2181
check docker logs -f containerA to watch the connection happening
If the connection can happen from the hosting operation system, and not from container B, then it try to temporary disable the firewalld to verify if this fixes the issue.
Add appropriate firewall configuration

# Masquerading allows for docker ingress and egress (this is the juicy bit)
firewall-cmd --zone=public --add-masquerade --permanen
# Reload firewall to apply permanent rules
firewall-cmd --reload

Further information on Docker networking time issue can be found here:

Installing Gradle

wget https://services.gradle.org/distributions/gradle-5.1-bin.zip -P /tmp
sudo unzip -d /opt/gradle /tmp/gradle-5.1-bin.zip
sudo vim /etc/profile.d/gradle.sh

paste the following lines:

export GRADLE_HOME=/opt/gradle/gradle-5.1
export PATH=${GRADLE_HOME}/bin:${PATH}

sudo chmod +x /etc/profile.d/gradle.sh
source /etc/profile.d/gradle.sh
gradle -v

Installing Kubernetes

https://www.techrepublic.com/article/how-to-install-kubernetes-on-centos-8/ https://www.youtube.com/watch?v=Araf8JYQn3w&list=PL34sAs7_26wNBRWM6BDhnonoA5FMERax0&index=3&t=0s

Installing Intellij

mkdir /opt/idea
Download and unzip Intellij in /opt/idea/
sh /opt/idea/idea-IU-183.6156.11/bin/idea.sh
follow the installation steps

Installing NodeJS

yum module list nodejs
sudo yum module install nodejs/development
dnf install nodejs
sudo yum module install nodejs/development
node --version

PuglieseWeb