Redis is an in-memory key-value store database. There are a few different ways to install redis-server in a Linux based system. To fit our purpose we are going to use the current (latest) stable release from REDIS.IO This process of installation is a bit complex because it requires you to build, compile and install the service manually. So hold on tight…

Install Build Dependencies

Before we download the source code we need to install the build dependencies meta package from ubuntu repositories.

sudo apt-get update

sudo apt-get install build-essential tcl

We are installing tcl package also to test the binaries after compilation

Download, Compile, Install Redis

After we are done with the compilation of the source code we can purge the files, so we can use /tmp folder to download and compile the source code.

Let’s change the directory to /tmp using

cd /tmp

Now we can download the tarball directly in this folder.

curl -O http://download.redis.io/redis-stable.tar.gz

Extract the tarball using

tar -xzvf redis-stable.tar.gz

Change the directory to redis-stable

cd redis-stable

Now we can compile the source code

make

After the compilation is complete, run the test suit to make sure that everything was built correctly

make test

Once the test is finished and everything is okay, it’s time to install the binaries into the system

sudo make install

Once the installation is successful, we can move on to configuring the redis-server

To check the installation process was successful or not, use the following command

redis-server --version

It should show something like below

Redis server v=5.0.5 sha=00000000:0 malloc=jemalloc-5.1.0 bits=64 build=2f03bf541f259179

Configure Redis Server

To start the configuration process we need to create a configuration directory in /etc using

sudo mkdir /etc/redis

The next step is to copy the sample configuration file that comes with the source code to the recently created /etc/redis directory, using

sudo cp ./redis.conf /etc/redis

Now it’s time to tweak a few configurations, open the file and edit like below

sudo nano /etc/redis/redis.conf

In the file search for supervised directive and change it to systemd, default is set to no.

The supervised directive will look like following

supervised systemd

Now, we can configure the persistent data storage location by finding the dir directive. Change it to /var/lib/redis

dir /var/lib/redis

Now, find the logfile directive and change it to logfile /var/log/redis/redis-server.log

logfile "/var/log/redis/redis-server.log"

Now, it’s time to find the pidfile directive, change it to pidfile /var/run/redis/redis-server.pid

pidfile /var/run/redis/redis-server.pid

redis must have access and write permission to these

• /var/lib/redis
• /var/log/redis/
• /var/run/redis/

directories in order to be able to dump data

Save the file and exit.

Create Redis User, Group and Data Directory

Now we can create redis user and group and also the directory we mentioned in the configuration file. We start by adding a user and group in the system

sudo adduser --system --group --no-create-home redis

Now once the user and group is created we can move on to creating the directory, we can create the directory by using

sudo mkdir /var/lib/redis /var/log/redis /var/run/redis

Provide redis user and group permission to the newly-created directory. To do that use the following

sudo chown redis:redis /var/lib/redis /var/log/redis /var/run/redis

Now, we can tweak the permission of this folder so that other regular users can not access this directory. To achieve that, use the following command

sudo chmod 770 /var/lib/redis /var/log/redis /var/run/redis

Once user, group, and directory permissions are in place, let’s create the systemd unit file to run redis as a service.

Create Systemd Unit File

Create a file named redis-server.service in /lib/systemd/system using the following command

sudo nano /lib/systemd/system/redis.service

Add the following content to the file, save it, and exit.

[Unit]
Description=Advanced key-value store
After=network.target

[Service]
ExecStart=/usr/local/bin/redis-server /etc/redis/redis.conf
ExecStop=/bin/kill -s TERM $MAINPID
PIDFile=/var/run/redis/redis-server.pid
TimeoutStopSec=0
Restart=always
User=redis
Group=redis
RuntimeDirectory=redis
RuntimeDirectoryMode=2755

UMask=007
PrivateTmp=yes
LimitNOFILE=65535
PrivateDevices=yes
ProtectHome=yes
ReadOnlyDirectories=/
ReadWriteDirectories=-/var/lib/redis
ReadWriteDirectories=-/var/log/redis
ReadWriteDirectories=-/var/run/redis

NoNewPrivileges=true
CapabilityBoundingSet=CAP_SETGID CAP_SETUID CAP_SYS_RESOURCE
MemoryDenyWriteExecute=true
ProtectKernelModules=true
ProtectKernelTunables=true
ProtectControlGroups=true
RestrictRealtime=true
RestrictNamespaces=true
RestrictAddressFamilies=AF_INET AF_INET6 AF_UNIX

# redis-server can write to its own config file when in cluster mode so we
# permit writing there by default. If you are not using this feature, it is
# recommended that you replace the following lines with "ProtectSystem=full".
ProtectSystem=true
ReadWriteDirectories=-/etc/redis

[Install]
WantedBy=multi-user.target
Alias=redis.service

Once this file is created in /lib/systemd/system/ create a symlink to it from /etc/sysetmd/system with

sudo ln -s /lib/systemd/system/redis-server.service /etc/systemd/system/redis.service

Please note that two directories are different, one is /lib another is /etc, although the child directory names are the same

Start Redis Server

Star the redis systemd process by using the following command

sudo systemctl start redis.service

The current status of redis-server can be checked with

sudo systemctl status redis

If everything went Okay, this should produce an output similar to following

● redis-server.service - Advanced key-value store
   Loaded: loaded (/lib/systemd/system/redis-server.service; enabled; vendor preset: enabled)
   Active: active (running) since Fri 2019-08-16 19:15:34 CEST; 11s ago
 Main PID: 30540 (redis-server)
    Tasks: 4 (limit: 4915)
   CGroup: /system.slice/redis-server.service
           └─30540 /usr/local/bin/redis-server 127.0.0.1:6379

Aug 16 19:15:34 isemg-p-ntr001 systemd[1]: Started Advanced key-value store.

Test Redis

To test that the newly installed redis-server instance is functioning properly, connect to redis server using the command line client for redis.

redis-cli

In the prompt that follows the above command, try ping command to test the connectivity with the server

127.0.0.1:6379> ping

It should return something like below

PONG

This action confirms the connection to redis server, now let’s try setting a key-value pair and retrieving it.

127.0.0.1:6379> set test "this is a test string from the blog"

The output should be similar as below

OK

Now let’s retrive the saved value

127.0.0.1:6379> get test

In the output it should return the text we set in the previous step

"this is a test string from the blog"

Once it’s confirmed, let’s restart the redis server and confirm that it’s persistent with data even after restart

sudo systemcrl restart redis

Now let’s try to retrive the stored value for key test

redis-cli
127.0.0.1:6379> get test
"this is a test string from lego python blog"

This confirms that redis installation is fully operational and ready for use.

Enjoy!