Installing Redis from Source on Linux

To install Redis on distributions like CentOS 7 or Ubuntu 18.04:

1. Download the source archive:

   wget http://download.redis.io/releases/redis-4.0.0.tar.gz
   

2. Extract the archive:

   tar -xvf redis-4.0.0.tar.gz
   

3. Compile the source:

   cd redis-4.0.0
   make
   

   If compilation fails due to missing dependencies:

   • Install make: apt install make
   • Install build tools: apt-get install build-essential tcl
   • If encountering jemalloc errrors, compile with:

     make CFLAGS="-DUSE_JEMALLOC=0" install
     

4. Install binaries:

   make install
   

5. Start the server:

   redis-server
   

6. Connect via client in another terminal:

   redis-cli
   

Starting Redis with Custom Ports

Redis can be started on non-default ports:

• Start server on port 6380:

  redis-server --port 6380
  

• Connect client to that port:

  redis-cli -p 6380
  

Using Configuration Files

Instead of command-line flags, use a config file for persistent settings.

1. Prepare a minimal config (redis-6379.conf):

   port 6379
   daemonize yes
   logfile "6379.log"
   dir /usr/local/redis/redis-4.0.0/data
   

   Generate it by stripping comments and blanks from the default redis.conf:

   cat redis.conf | grep -v "^#" | grep -v "^$" > redis-6379.conf
   

2. Start Redis using the config:

   redis-server redis-6379.conf
   

3. Verify the process:

   ps -ef | grep redis-server
   

Managing Multiple Redis Instances

Organize configs in a dedicated directory for multi-instance setups.

1. Create a conf directory and populate it:

   mkdir conf
   mv redis-6379.conf conf/
   cp conf/redis-6379.conf conf/redis-6380.conf
   

2. Edit conf/redis-6380.conf to change:

   port 6380
   logfile "6380.log"
   

3. Launch both instances:

   redis-server conf/redis-6379.conf
   redis-server conf/redis-6380.conf
   

4. Test connectivity:

   redis-cli -p 6379
   # Set and get key in instance 6379
   
   redis-cli -p 6380
   # Set and get key in instance 6380
   

Stopping Redis Instances

To stop a running instance:

1. Find its PID:

   ps -ef | grep redis-server
   

2. Terminate it:

   kill -9 <PID>