redis systemd unit file

redis.service

Description=Redis In-Memory Data Store                       
After=network.target                                         
                                                             
[Service]                                                    
Type=forking                                                 
User=redis                                                   
Group=redis                                                  
Environment=statedir=/run/redis                              
PermissionsStartOnly=true                                    
PIDFile=/run/redis/redis.pid                                 
ExecStartPre=/bin/touch /var/log/redis.log                   
ExecStartPre=/bin/chown redis:redis /var/log/redis.log       
ExecStartPre=/bin/mkdir -p ${statedir}                       
ExecStartPre=/bin/chown -R redis:redis ${statedir}           
ExecStart=/usr/local/bin/redis-server /etc/redis/redis.conf  
ExecStop=/usr/local/bin/redis-cli shutdown                   
ExecReload=/bin/kill -USR2 $MAINPID                          
Restart=always                                               
RestartSec=3                                                 
                                                             
[Install]                                                    
WantedBy=multi-user.target                                   

I believe you forgot [Unit] as a first line