Initial Server Setup CentOS + Docker

instructions.txt

# ============ Create separate user ============
https://www.digitalocean.com/community/tutorials/initial-server-setup-with-centos-7
https://www.digitalocean.com/community/tutorials/how-to-create-a-sudo-user-on-centos-quickstart
local$ ssh root@server_ip_address
# adduser username
# passwd username
# usermod -aG wheel username


# ============ Copy your SSH key to server ============
local$ ssh-copy-id username@server_ip_address


# ============ Change SSH port to non-standart ============
$ sudo firewall-cmd --zone=public --add-port=2222/tcp --permanent
$ sudo firewall-cmd --reload
Check new rules
$ sudo firewall-cmd --list-all
Open SSHD config file
$ sudo vim /etc/ssh/sshd_config
Change Port 22 -> Port 2222
$ sudo systemctl restart sshd

* If service was not able to restart (Job for sshd.service failed because the control process exited with error code...), then check logs:
$ tail /var/log/secure
If it says: "error: Bind to port 2222 on 0.0.0.0 failed: Permission denied.", then first check if the port is open. If it's open, then it's probably because of the SELinux. To fix this run:
$ sudo semanage port -a -t ssh_port_t -p tcp 2222
$ sudo systemctl restart sshd


# ============ Disable SSH root login ============
$ sudo vim /etc/ssh/sshd_config
Change PermitRootLogin yes -> PermitRootLogin no
$ sudo systemctl restart sshd


# ============ Disable SSH password authentication (be careful!) ============
$ sudo vim /etc/ssh/sshd_config
Change PasswordAuthentication yes -> PasswordAuthentication no
$ sudo systemctl restart sshd
To test if you can connect to a host using password authentication and explicitly deny public key authentication:
local$ ssh -o PreferredAuthentications=password -o PubkeyAuthentication=no user@host


# ============ Add shortcut for fast SSH login ============
local$ vim ~/.ssh/config
Add:
Host server1
  HostName server_ip_address
  User username
  Port 2222
Save and check
local$ ssh server1


# ============ Enable swap file ============
https://www.digitalocean.com/community/tutorials/how-to-add-swap-on-centos-7
$ sudo fallocate -l 4G /swapfile
$ sudo chmod 600 /swapfile
$ sudo mkswap /swapfile
$ sudo swapon /swapfile
$ sudo vim /etc/fstab     ->    /swapfile   swap    swap    sw  0   0


# ============ Install Docker & Docker-compose ============
https://docs.docker.com/install/linux/docker-ce/centos/#set-up-the-repository
$ sudo yum install -y yum-utils device-mapper-persistent-data lvm2
$ sudo yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
$ sudo yum install docker-ce
$ sudo systemctl start docker
$ sudo systemctl enable docker

Add user to docker group
https://docs.docker.com/install/linux/linux-postinstall/#manage-docker-as-a-non-root-user
sudo groupadd docker
sudo usermod -aG docker $USER
Log out and log back in so that your group membership is re-evaluated.


# ============ Fix “setlocale: LC_CTYPE: cannot change locale (UTF-8): No such file or directory” during login ============
sudo vim /etc/environment
LANG=en_US.utf-8
LC_ALL=en_US.utf-8