How To Set Up Your Linode For Maximum Awesomeness

So, you followed the advice in my Linode Hosting Review and decided to host your website with Linode. Excellent choice!

But, if you’re new to the command line (perhaps you are familiar with CPanel or Plesk?) or you’ve never setup a server from scratch before, you may be wondering what dark magic vudu is required to get up and running.

Well, you’ve come to the right place!

The Command Line Is Hard (…at first)

I’ve set up at least five new servers with Linode and each time I complete the ritual, I learn new incantations that make the Linux angels sing. I’m pretty happy with my current recipe.

Setting up a new server can be confusing, so using a tutorial like this one is a good idea the first time you do it.

Tutorial: How To Set Up Your Linode

In this guide, I will demonstrate how to set up a fresh Ubuntu server from scratch, update everything, install essential software, lock down the server to make it more resilient against basic attacks and denial-of-service, improve server stability, setup automatic backups to another server, and finally install common software like Nginx, MySQL, Python, Node, etc.

A Note About This Guide

I originally compiled this guide as a .txt file of notes for myself, but decided to share it in case anyone finds it useful. If you’re looking for something straight from the horse’s mouth, Linode offers guides that cover how to set up a new server, but some of the info is out of date.

Let’s get started!

Provision a New Linode

First, you need to provision a new Linode. Using Linode’s web UI, it’s quite easy. Select your desired Linode size. If you’re unsure, choose the smallest size. You can always resize it later. Select “Ubuntu 12.04 LTS” as your OS. You’ll be asked to create a password for the root user.

After a few minutes, your server will be ready. Now, it’s time to connect to it!

Connecting to Your Server

First, open Terminal on your Mac. On Windows, you’ll want to use putty, since Windows doesn’t come with a proper terminal.

To connect to your server, type this into your terminal and hit Enter:

ssh root@<your server ip>

Of course, replace <your server ip> with your Linode’s actual IP address, which you can find on the “Remote Access” tab in the control panel.

This command launches the SSH program and asks it to connect to your server with the username root, which is the default Ubuntu user. You will be prompted for the root password you created earlier.

Basic Ubuntu Setup

To set up your new server, execute the following commands.

Set the hostname

Set the server hostname. Any name will do — just make it memorable. In this example, I chose “future”.

echo "future" > /etc/hostname
hostname -F /etc/hostname

Let’s verify that it was set correctly:

hostname

Set the fully-qualified domain name

Set the FQDN of the server by making sure the following text is in the /etc/hosts file:

    127.0.0.1          localhost.localdomain   localhost
    127.0.1.1          ubuntu
    <your server ip>   future.<your domain>.net       future

It is useful if you add an A record that points from some domain you control (in this case I used “future.<your domain>.net”) to your server IP address. This way, you can easily reference the IP address of your server when you SSH into it, like so:

ssh future.<your domain>.net

If you’re curious, you can read more about the /etc/hosts file.

Set the time

Set the server timezone:

dpkg-reconfigure tzdata

Verify that the date is correct:

date

Update the server

Check for updates and install:

aptitude update
aptitude upgrade

Basic Security Setup

Create a new user

The root user has a lot of power on your server. It has the power to read, write, and execute any file on the server. It’s not advisable to use root for day-to-day server tasks. For those tasks, use a user account with normal permissions.

Add a new user:

adduser <your username>

Add the user to the sudo group:

usermod -a -G sudo <your username>

This allows you to perform actions that require root priveledge by simply prepending the word sudo to the command. You may need to type your password to confirm your intentions.

Login with new user:

exit
ssh <your username>@<your server ip>

Set up SSH keys

SSH keys allow you to login to your server without a password. For this reason, you’ll want to set this up on your primary computer (definitely not a public or shared computer!). SSH keys are very convenient and don’t make your server any less secure.

If you’ve already generated SSH keys before (maybe for your GitHub account?), then you can skip the next step.

Generate SSH keys

Generate SSH keys with the following command:

(NOTE: Be sure to run this on your local computer — not your server!)

ssh-keygen -t rsa -C "<your email address>"

When prompted, just accept the default locations for the keyfiles. Also, you’ll want to choose a nice, strong password for your key. If you’re on Mac, you can save the password in your keychain so you won’t have to type it in repeatedly.

Now you should have two keyfiles, one public and one private, in the ~/.ssh folder.

If you want more information about SSH keys, GitHub has a great guide.

Copy the public key to server

Now, copy your public key to the server. This tells the server that it should allow anyone with your private key to access the server. This is why we set a password on the private key earlier.

From your local machine, run:

scp ~/.ssh/id_rsa.pub <your username>@<your server ip>:

On your Linode, run:

mkdir .ssh
mv id_rsa.pub .ssh/authorized_keys
chown -R <your username>:<your username> .ssh
chmod 700 .ssh
chmod 600 .ssh/authorized_keys

Disable remote root login and change the SSH port

Since all Ubuntu servers have a root user and most servers run SSH on port 22 (the default), criminals often try to guess the root password using automated attacks that try many thousands of passwords in a very short time. This is a common attack that nearly all servers will face.

We can make things substantially more difficult for automated attackers by preventing the root user from logging in over SSH and changing our SSH port to something less obvious. This will prevent the vast majority of automatic attacks.

Disable remote root login and change SSH port:

sudo nano /etc/ssh/sshd_config

Set “Port” to “44444” and “PermitRootLogin” to “no”. Save the file and restart the SSH service:

sudo service ssh restart

In this example, we changed the port to 44444. So, now to connect to the server, we need to run:

ssh <your username>@future.<your domain>.net -p 44444

Update: Someone posted this useful note about choosing an SSH port on Hacker News:

Make sure your SSH port is below 1024 (but still not 22). Reason being if your Linode is ever compromised a bad user may be able to crash sshd and run their own rogue sshd as a non root user since your original port is configured >1024. (More info here)

Advanced Security Setup

Prevent repeated login attempts with Fail2Ban

Fail2Ban is a security tool to prevent dictionary attacks. It works by monitoring important services (like SSH) and blocking IP addresses which appear to be malicious (i.e. they are failing too many login attempts because they are guessing passwords).

Install Fail2Ban:

sudo aptitude install fail2ban

Configure Fail2Ban:

sudo cp /etc/fail2ban/jail.conf /etc/fail2ban/jail.local
sudo nano /etc/fail2ban/jail.local

Set “enabled” to “true” in the [ssh-ddos] section. Also, set “port” to “44444” in the [ssh] and [ssh-ddos] sections. (Change the port number to match whatever you used as your SSH port).

Save the file and restart Fail2Ban to put the new rules into effect:

sudo service fail2ban restart

Add a firewall

We’ll add an iptables firewall to the server that blocks all incoming and outgoing connections except for ones that we manually approve. This way, only the services we choose can communicate with the internet.

The firewall has no rules yet. Check it out:

sudo iptables -L

Setup firewall rules in a new file:

sudo nano /etc/iptables.firewall.rules

The following firewall rules will allow HTTP (80), HTTPS (443), SSH (44444), ping, and some other ports for testing. All other ports will be blocked.

Paste the following into /etc/iptables.firewall.rules:

*filter

#  Allow all loopback (lo0) traffic and drop all traffic to 127/8 that doesn't use lo0
-A INPUT -i lo -j ACCEPT
-A INPUT ! -i lo -d 127.0.0.0/8 -j REJECT

#  Accept all established inbound connections
-A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT

#  Allow all outbound traffic - you can modify this to only allow certain traffic
-A OUTPUT -j ACCEPT

#  Allow HTTP and HTTPS connections from anywhere (the normal ports for websites and SSL).
-A INPUT -p tcp --dport 80 -j ACCEPT
-A INPUT -p tcp --dport 443 -j ACCEPT

#  Allow ports for testing
-A INPUT -p tcp --dport 8080:8090 -j ACCEPT

#  Allow ports for MOSH (mobile shell)
-A INPUT -p udp --dport 60000:61000 -j ACCEPT

#  Allow SSH connections
#  The -dport number should be the same port number you set in sshd_config
-A INPUT -p tcp -m state --state NEW --dport 44444 -j ACCEPT

#  Allow ping
-A INPUT -p icmp -m icmp --icmp-type 8 -j ACCEPT

#  Log iptables denied calls
-A INPUT -m limit --limit 5/min -j LOG --log-prefix "iptables denied: " --log-level 7

#  Reject all other inbound - default deny unless explicitly allowed policy
-A INPUT -j REJECT
-A FORWARD -j REJECT

COMMIT

Activate the firewall rules now:

sudo iptables-restore < /etc/iptables.firewall.rules

Verify that the rules were installed correctly:

sudo iptables -L

Activate the firewall rules on startup:

sudo nano /etc/network/if-pre-up.d/firewall

Paste this into the /etc/network/if-pre-up.d/firewall file:

#!/bin/sh
/sbin/iptables-restore < /etc/iptables.firewall.rules

Set the script permissions:

sudo chmod +x /etc/network/if-pre-up.d/firewall

Get an email anytime a user uses sudo

I like to get an email anytime someone uses sudo. This way, I have a “paper trail” of sorts, in case anything bad happens to my server. I use a Gmail filter to file these away and only look at them occasionally.

Create a new file for the sudo settings:

sudo nano /etc/sudoers.d/my_sudoers

Add this to the file:

Defaults    mail_always
Defaults    mailto="feross@feross.org"

Set permissions on the file:

sudo chmod 0440 /etc/sudoers.d/my_sudoers

This is isn’t mentioned anywhere on the web, as far as I know, but in order for the “mail on sudo use” feature to work, you need to install an MTA server. sendmail is a good choice:

sudo aptitude install sendmail

Now, you should get an email anytime someone uses sudo!

Improve Server Stability

VPS servers can easily run out of memory during traffic spikes.

For example, most people don’t change Apache’s default setting which allows 150 clients to connect simultaneously. This is way too large a number for a typical VPS server. Let’s do the math. Apache’s processes are typically ~25MB each. If our website gets a temporary traffic spike and 150 processes launch, we’ll need 3750MB of memory on our server. If we don’t have this much (and we don’t!), then the OS will grind to a halt as it swaps memory to disk to make room for new processes, but then immediately swaps the stuff on disk back into memory.

No useful work gets done once swapping happens. The server can be stuck in this state for hours, even after the traffic rush has subsided. During this time, very few web requests will get serviced.

It’s very important to configure your applications so memory swapping does not occur. If you use Apache, you should set MaxClients to something more reasonable like 20 or 30. There are many other optimizations to make, too. Linode has a Library article with optimizations for Apache, MySQL, and PHP.

Reboot server on out-of-memory condition

Still, in cases where something goes awry, it is good to automatically reboot your server when it runs out of memory. This will cause a minute or two of downtime, but it’s better than languishing in the swapping state for potentially hours or days.

You can leverage a couple kernel settings and Lassie to make this happen on Linode.

Adding the following two lines to your /etc/sysctl.conf will cause it to reboot after running out of memory:

vm.panic_on_oom=1
kernel.panic=10

The vm.panic_on_oom=1 line enables panic on OOM; the kernel.panic=10 line tells the kernel to reboot ten seconds after panicking.

Read more about rebooting when out of memory on Linode’s wiki.

Miscellaneous nice-to-haves

These next things are not required (in fact, nothing in this guide really is), but are nice to do.

Set up reverse DNS

The reverse DNS system allows one to determine the domain name that lives at a given IP address. This is useful for network troubleshooting — (ping, traceroute, etc.), as well as email anti-spam measures (read more on Wikipedia).

It’s pretty easy to set up. From the Linode Manager, select your Linode, click on “Remote Access”, then click on “Reverse DNS” (under “Public IPs”). Type in your domain and that’s it!

Set up a private IP address

Private IPs are useful for communicating data on the Linode network, i.e. Linode to Linode. This is handy if you have multiple Linodes (say, one for your web server and one for your database). Private network traffic is more secure (only other Linode customers can see it, vs. the whole internet), faster (the traffic never has to leave the datacenter if both Linodes are in the same datacenter), and free (doesn’t count towards your monthly bandwidth quota).

I currently put my database server on it’s own Linode, so that I can scale it independently of my frontend servers and debug performance issues easier since the systems are isolated. This hasn’t been super-handy yet, but if one of my sites gets a huge traffic rush, I bet it will be immensely useful.

It’s easy to set up. On the Remote Access tab, click Add a Private IP.

Then, edit the file /etc/network/interfaces to contain:

# The loopback interface
auto lo
iface lo inet loopback

# Configuration for eth0 and aliases

# This line ensures that the interface will be brought up during boot.
auto eth0 eth0:0

# eth0 - This is the main IP address that will be used for most outbound connections.
# The address, netmask and gateway are all necessary.
iface eth0 inet static
 address 12.34.56.78
 netmask 255.255.255.0
 gateway 12.34.56.1

# eth0:0 - Private IPs have no gateway (they are not publicly routable) so all you need to
# specify is the address and netmask.
iface eth0:0 inet static
 address 192.168.133.234
 netmask 255.255.128.0

Of course, adjust the IP addresses to reflect your own addresses from the Remote acess tab.

Then, restart your Linode and remove DHCP since we’re using static networking now:

sudo aptitude remove isc-dhcp-client dhcp3-client dhcpcd

More info about this on Linode’s website: Linux Static IP Configuration

Configuring your applications and your database to route traffic over the local network is another issue, not covered here.

Install Useful Server Software

At this point, you have a pretty nice server setup. Congrats! But, your server still doesn’t do anything useful. Let’s install some software.

Install a compiler

A compiler is often required to install Python packages and other software, so let’s just install one up-front.

sudo aptitude install build-essential

Install MySQL

Install MySQL:

sudo aptitude install mysql-server libmysqlclient-dev

Set root password when prompt asks you.

Verify that MySQL is running.

sudo netstat -tap | grep mysql

For connecting to MySQL, instead of the usual PHPMyAdmin, I now use Sequel Pro, a free app for Mac.

Improve MySQL security

Before using MySQL in production, you’ll want to improve your MySQL installation security. Run:

mysql_secure_installation

This will help you set a password for the root account, remove anonymous-user accounts, and remove the test database.

Keep your MySQL tables in tip-top shape

Over time your MySQL tables will get fragmented and queries will take longer to complete. You can keep your tables in top shape by regularly running OPTIMIZE TABLE on all your tables. But, since you’ll never remember to do this regularly, we should set up a cron job to do this.

Open up your crontab file:

crontab -e

Then, add the following line:

@weekly mysqlcheck -o --user=root --password=<your password here> -A

Also, you can try manually running the above command to verify that it works correctly.

Backup your MySQL databases

The excellent automysqlbackup utility can automatically make daily, weekly, and monthly backups of your MySQL database.

Install it:

sudo aptitude install automysqlbackup

Now, let’s configure it. Open the configuration file:

sudo nano /etc/default/automysqlbackup

By default, your database backups get stored in /var/lib/automysqlbackup which isn’t very intuitive. I recommend changing it to a folder within your home directory. To do this, find the line that begins with BACKUPDIR= and change it to BACKUPDIR="/home/<your username>/backups/"

You also want to get an email if an error occurs, so you’ll know if automatic backups stop working for some reason. Find the line that begins with MAILADDR= and change it to MAILADDR="<your email address>".

Close and save the file. That’s it!

Install Python

Install Python environment:

sudo aptitude install python-pip python-dev
sudo pip install virtualenv

This creates a global “pip” command to install Python packages. Don’t use it, because packages will be installed globally. Instead, use virtualenv.

Create a new virtualenv Python environment with:

virtualenv --distribute <environment_name>

Switch to the new environment with:

cd <environment_name>
source bin/activate

Note that the name of your environment is added to your command prompt.

Install Python packages with “pip” inside of virtualenv:

pip search <package_name>
pip install <package_name>

This is the best Python workflow that I’ve found. Let me know if you know of a better way to manage Python packages and Python installations.

Install Nginx

sudo aptitude install nginx

Install Apache

sudo aptitude install apache2

Install PHP5

sudo aptitude install php5 libapache2-mod-php5 php5-mysql
sudo service apache2 restart

Install Node.js

sudo aptitude update
sudo aptitude install python-software-properties python g++ make
sudo add-apt-repository ppa:chris-lea/node.js
sudo aptitude update
sudo aptitude install nodejs

Install MongoDB

Follow instructions on 10gen’s site: Install MongoDB on Ubuntu.

Install Redis

sudo aptitude install redis-server

Setup Automatic Backups

Backups are really important. Linode offers a paid backup service that’s really convenient if you accidentally destroy something and need to restore your Linode quickly. It’s $5 per month for the smallest Linode. I enable it on all my Linodes.

If you want even more peace of mind (or don’t want to pay for Linode’s backup service) you can roll your own simple backup solution using rsync.

You will need access to another Linux server (maybe another Linode?) or a home server. I just installed Ubuntu on an old desktop computer to use as a backup server.

We’re going to create a weekly cronjob that backs up our Linode’s home directory to a backup server. I keep all the files that I would want to backup in my home folder, so this works for me.

Open your crontab:

crontab -e

Add this line to the file:

@weekly rsync -r -a -e "ssh -l <your username on backup server> -p <ssh port number of backup server>" --delete /home/<your username> <hostname or ip address of backup server>:/path/to/some/directory/on/backup/server

I recommend running the above command manually to make sure you have it right before adding it to your crontab file.

That’s it!

Linode rocks!

If, after reading this, you want to sign up for Linode, use this link and I’ll get a couple weeks of free hosting. If you prefer not to, here’s the plain link: Linode.com

Happy hacking!

(View this post’s changelog on Github)

(If you liked this, you might like Freedom of Speech on the Internet.)

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Feross Aboukhadijeh Hey, thanks for reading! I'm Feross Aboukhadijeh, a programmer, designer, teacher, and mad scientist. I am currently building WebTorrent, a streaming BitTorrent client for the browser, powered by WebRTC. In my free time, I work on StudyNotes, a website to help students study better and get into college.

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