CentOS Server Setup

CENTOS-SETUP-GUIDE.rst

CentOS Server Setup

Initial Setup

1. Change the default root password using # passwd.

2. Copy firewall shell script and modify it accordingly. Run it.

3. Setup SSH by editing /etc/ssh/sshd_config and adding/editing the following lines. Note each allowed SSH user must replace USERNAME1, USERNAME2, etc. below.

   Port SSH_PORT
   PermitRootLogin no
   UseDNS no
   AllowUsers USERNAME1 USERNAME2
   

4. Now restart the SSH service: # systemctl restart sshd.service and note any change in SSH ports for when you reconnect.

5. Add desired users using # adduser USERNAME and set a default password # passwd USERNAME.

6. Remove the default "Fedora cloud user" account using # userdel fedora -r.

7. Allow users sudo permission by running # visudo and adding a USERNAME ALL=(ALL) ALL entry for each allowed USERNAME.

8. Update the system: # yum update and # yum upgrade.

9. Install some important packages: # yum group install "Development Tools", # yum install libxslt-devel libxml2-devel..

SSH Key Setup

On your local PC:

1. Create a key:

   $ cd ~/.ssh
   $ ssh-keygen -t rsa -f USERNAME_rsa
   $ chmod 700 ~/.ssh
   $ chmod 600 ~/.ssh/USERNAME_rsa
   

2. Copy the public key to the server, eg. $ scp -P 7331 ~/.ssh/USERNAME_rsa.pub USERNAME@SERVER_ADDRESS:/home/USERNAME/.

3. Ensure the correct SELinux contexts are set: $ restorecon -Rv ~/.ssh.

On the CentOS server:

1. Append the public key to the profile's authorized_keys SSH file and set file permissions:

   $ cat USERNAME_rsa.pub >> ~/.ssh/authorized_keys
   $ chmod 700 ~/.ssh
   $ chmod 600 ~/.ssh/authorized_keys
   

2. Ensure the correct SELinux contexts are set: $ restorecon -Rv ~/.ssh.

Rename Server Host

1. Open /etc/sysconfig/network file and modify the HOSTNAME= value to match your FQDN host name: $ sudo vi /etc/sysconfig/network.
2. Open /etc/hosts file and modify any line referencing the old HOSTNAME to point to the new HOSTNAME.
3. Run the hostname command to see the current/old HOSTNAME and then run again with the first argument to set the new HOSTNAME: $ sudo hostname and $ sudo hostname NEW_HOSTNAME.
4. Restart the networking service: $ sudo /etc/init.d/network restart.

Setup Apache HTTPD

1. Install httpd: # yum install httpd httpd-itk mod_wsgi mod_ssl openssl.
2. Start the service: # systemctl start httpd.service.
3. Check the status: # systemctl status httpd.service -l.
4. Open a web browser and point it to server's IP address.
5. Enable automatic start of httpd at boot: # systemctl enable httpd.service.
6. Copy vhosts.conf httpd config file to /etc/httpd/conf.d/ and restart httpd: # systemctl restart httpd.service.

Auto-mounting External Drive

1. Find the device by its mount point: # fstab -l.
2. Get the devices associated UUID: $ ls -l /dev/disk/by-uuid (this will allow you to plugin the device into any other port on the computer).
3. Create the mount directory: # mkdir /mnt/rb1tb.
4. Edit the fstab file: # vi /etc/fstab.
5. Add the following line to the file: UUID=43d65df3-ad4e-447e-ac97-a992c1dbe427 /mnt/rb1tb ext4 defaults 1 1.

Configuration of Python

1. Install easy_install: # yum install python-setuptools.
2. Install pip: # easy_install pip.

Adding a Script to Cron

1. Set your script to be executable: $ chmod 755 script.py.
2. Create a symbolic link to the file in cron: $ ln -s /PATH/TO/script.py /etc/cron.hourly/.

Installing Git-Annex

NOTE 1: If you are using the steps below for your client computer with Fedora/CentOS/RHEL, it is recommended to replace the references to /usr/local/bin with $HOME/bin. Note also that if you do this, you do not need to run the associated command with sudo.

NOTE 2: If installing on a client computer with Fedora/CentOS/RHEL: skip step 5 and make sure $HOME/bin is in your PATH environment variable. If it isn't add export PATH=$PATH:$HOME/bin to ~/.bashrc and run $ source ~/.bashrc.

1. Install dependencies via YUM: $ sudo yum install haskell-platform gnutls-devel libgsasl-devel libxml2-devel zlib-devel ghc-zlib-devel libidn-devel.
2. Update cabal: $ cabal update.
3. If needed, upgrade cabal: $ cabal install cabal-install.
4. Install c2hs: $ sudo cabal install c2hs --bindir=/usr/local/bin/.
5. Create symbolic link for c2hs within /usr/sbin so you can run it as sudo or root: $ sudo ln -s /usr/local/bin/c2hs /usr/sbin/.
6. Finally, install git-annex: $ sudo cabal install git-annex --bindir=/usr/local/bin/.
7. If you encounter any errors with the installation, with regards to the Glasgow Haskell Compiler (ghc) see below.

Error with ghc While Installing Git-Annex

You will have to compile the newest version by going to the website http://justhub.org/download (as recommended on http://www.haskell.org/platform/linux.html).

1. Download the rpm for CentOS 6: $ wget http://sherkin.justhub.org/el6/RPMS/x86_64/justhub-release-2.0-4.0.el6.x86_64.rpm.
2. Add the rpm to Yum: $ sudo -ivh justhub-release-2.0-4.0.el6.x86_64.rpm.
3. Now install Haskell: $ sudo yum install haskell.
4. You might have received an error about the existing compiler, remove it using: $ sudo yum remove [package(s)].

Setup Crontab

Users can be allowed to create cron jobs when their username is specified using the following:

1. Move or delete the .deny file:

   $ sudo mv /etc/cron.deny /etc/cron.deny.NOT_USED
   

2. Add usernames (one per line) to the .allow file to give users access to create cron jobs:

   $ sudo vi /etc/cron.allow
   (add username, save, and exit the file)
   

3. Specified users can now use the $ crontab -e command to specify their own cron jobs.

Allow User Boot Scripts

To allow users to run scripts when the server boots up, follow these steps:

1. Give each user an executable boot.sh shell file in their home directory. The user can edit this file to add commands to be ran when the system boots.

2. Open /etc/rc.local and add the following line for each user that has a boot.sh file. Replace USERNAME with their username.

   (su -c /home/USERNAME/boot.sh USERNAME) &
   

3. The next time the server restarts each of the specified boot.sh scripts in rc.local will be run as the respective user.