Installing Varnish Using a Package Manager

Compiling from source is all fun and games, but it takes a lot of time. If you get one of the dependencies wrong or you install the wrong version of a dependency, you’re going to have a bad day. Why bother doing it the hard way (unless you have your reasons) if you can easily install Varnish using the package manager of your operating system?

Here’s a list of package managers you can use according to your operating system:

• APT on Ubuntu and Debian

• YUM on Red Hat and CentOS

• PKG on FreeBSD

Installing Varnish on Ubuntu and Debian

In simple terms, we can say that the Ubuntu and the Debian distributions are related. Ubuntu is a Debian-based operating system. Both distributions use the APT package manager. But even though the installation of Varnish is similar on both distributions, there are subtle differences. That’s why there are different APT repository channels for Ubuntu and Debian.

Here’s how you install Varnish on Ubuntu, assuming you’re running the Ubuntu 14.04 LTS (Trusty Tahr) version:

apt-get install apt-transport-https
curl https://repo.varnish-cache.org/GPG-key.txt | apt-key add -
echo "deb https://repo.varnish-cache.org/ubuntu/ trusty varnish-4.1" \
     >> /etc/apt/sources.list.d/varnish-cache.list
apt-get update
apt-get install varnish

If you’re running Debian, here’s how you can install Varnish on Debian 8 (Jessie):

apt-get install apt-transport-https
curl https://repo.varnish-cache.org/GPG-key.txt | apt-key add -
echo "deb https://repo.varnish-cache.org/debian/ jessie varnish-4.1"\
    >> /etc/apt/sources.list.d/varnish-cache.list
apt-get update
apt-get install varnish

Installing Varnish on Red Hat and CentOS

There are three main distributions in the Red Hat family of operating systems:

• Red Hat Enterprise: the paid enterprise version

• CentOS: the free version

• Fedora: the bleeding-edge desktop version

All three of them have the YUM package manager, but we’ll primarily focus on both Red Hat and CentOS, which have the same installation procedure.

If you’re on Red Hat or CentOS version 7, here’s how you install Varnish:

yum install epel-release
rpm --nosignature -i https://repo.varnish-cache.org/redhat/varnish-4.1.el7.rpm
yum install varnish

If you’re on Red Hat or CentOS version 6, here’s how you install Varnish:

yum install epel-release
rpm --nosignature -i https://repo.varnish-cache.org/redhat/varnish-4.1.el6.rpm
yum install varnish

The Configuration File

The first challenge is to find where the configuration file is located on your system. This depends on the Linux distribution, but also on the service manager your operating system is running.

If your operating system uses the systemd service manager, the Varnish configuration file will be located in a different folder than it usually would be. Systemd is enabled by default on Debian Jessie and CentOS 7. Ubuntu Trusty Tahr still uses Sysv.

If you want to know where the configuration file is located on your operating system (given that you installed Varnish via a package manager), have a look at Table 2-1.

If you change the content of the configuration file, you need to reload the Varnish service to effectively load these settings. Run the following command to make this happen:

sudo service varnish reload

Some Remarks on Systemd on Ubuntu and Debian

If you’re on Ubuntu or Debian and you’re using the systemd service manager, there are several things you need to keep in mind.

First of all, you need to copy the configuration file to the right folder in order to override the default settings. Here’s how you do that:

sudo cp /lib/systemd/system/varnish.service /etc/systemd/system

If you’re planning to make changes to that file, don’t forget that the results are cached in memory. You need to reload systemd in order to have your changes loaded from the file. Here’s how you do that:

sudo systemctl daemon-reload

That doesn’t mean Varnish will be started with the right startup options, only that systemd knows the most recent settings. You will still need to reload the Varnish service to load the configuration changes, like this:

sudo service varnish reload

Startup Options

By now you already know that the sole purpose of the configuration file is to feed the startup options to the varnishd program. In theory, you don’t need a service manager: you can manually start Varnish by running varnishd yourself and manually assigning the startup options.

usage: varnishd [options]
    -a address[:port][,proto]    # HTTP listen address and port (default: *:80)
                                 #   address: defaults to loopback
                                 #   port: port or service (default: 80)
                                 #   proto: HTTP/1 (default), PROXY
    -b address[:port]            # backend address and port
                                 #   address: hostname or IP
                                 #   port: port or service (default: 80)
    -C                           # print VCL code compiled to C language
    -d                           # debug
    -F                           # Run in foreground
    -f file                      # VCL script
    -h kind[,hashoptions]        # Hash specification
                                 #   -h critbit [default]
                                 #   -h simple_list
                                 #   -h classic
                                 #   -h classic,<buckets>
    -i identity                  # Identity of varnish instance
    -j jail[,jailoptions]        # Jail specification
                                 #   -j unix[,user=<user>][,ccgroup=<group>]
                                 #   -j none
    -l vsl[,vsm]                 # Size of shared memory file
                                 #   vsl: space for VSL records [80m]
                                 #   vsm: space for stats counters [1m]
    -M address:port              # Reverse CLI destination
    -n dir                       # varnishd working directory
    -P file                      # PID file
    -p param=value               # set parameter
    -r param[,param...]          # make parameter read-only
    -S secret-file               # Secret file for CLI authentication
    -s [name=]kind[,options]     # Backend storage specification
                                 #   -s malloc[,<size>]
                                 #   -s file,<dir_or_file>
                                 #   -s file,<dir_or_file>,<size>
                                 #   -s file,<dir_or_file>,<size>,<granularity>
                                 #   -s persistent (experimental)
    -T address:port              # Telnet listen address and port
    -t TTL                       # Default TTL
    -V                           # version
    -W waiter                    # Waiter implementation
                                 #   -W epoll
                                 #   -W poll

The varnishd documentation page has more detailed information about all of the startup options.

Let’s take a look at some of the typical startup options you’ll encounter when setting up Varnish. The examples I use represent the ones coming from /etc/default/varnish on an Ubuntu system that uses Sysv as the service manager.

DAEMON_OPTS="-a :80 \
             -a :81,PROXY \
             -T localhost:6082 \
             -f /etc/varnish/default.vcl \
             -S /etc/varnish/secret \
             -s malloc,3g \
             -j unix,user=www-data \"

DAEMON_OPTS="-a :80 \
             -a :81,PROXY \
             -T localhost:6082 \
             -f /etc/varnish/default.vcl \
             -S /etc/varnish/secret \
             -s malloc,3g \
             -j unix,user=www-data \
             -l 100m,10m \
             -t 60 \
             -p feature=_++esi_disable_xml_check \
             -p connect_timeout=5 \
             -p first_byte_timeout=10 \
             -p between_bytes_timeout=2"