4.2. Prioritizing Network Traffic

Procedure 4.2. Setting Network Priorities for File Sharing Services

1. Attach the net_prio subsystem to the /cgroup/net_prio cgroup:

   ~]# mkdir sys/fs/cgroup/net_prio
   ~]# mount -t cgroup -o net_prio none sys/fs/cgroup/net_prio

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2. Create two cgroups, one for each service:

   ~]# mkdir sys/fs/cgroup/net_prio/nfs_high
   ~]# mkdir sys/fs/cgroup/net_prio/samba_low

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3. To automatically move the nfs services to the nfs_high cgroup, add the following line to the /etc/sysconfig/nfs file:

   CGROUP_DAEMON="net_prio:nfs_high"

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   This configuration ensures that nfs service processes are moved to the nfs_high cgroup when the nfs service is started or restarted.
4. The smbd service does not have a configuration file in the /etc/sysconfig directory. To automatically move the smbd service to the samba_low cgroup, add the following line to the /etc/cgrules.conf file:

   *:smbd                net_prio                samba_low

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   Note that this rule moves every smbd service, not only /usr/sbin/smbd, into the samba_low cgroup.
   You can define rules for the nmbd and winbindd services to be moved to the samba_low cgroup in a similar way.
5. Start the cgred service to load the configuration from the previous step:

   ~]# systemctl start cgred
   Starting CGroup Rules Engine Daemon:                       [  OK  ]
   

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6. For the purposes of this example, let us assume both services use the eth1 network interface. Define network priorities for each cgroup, where 1 denotes low priority and 10 denotes high priority:

   ~]# echo "eth1 1" > /sys/fs/cgroup/net_prio/samba_low/net_prio.ifpriomap
   ~]# echo "eth1 10" > /sys/fs/cgroup/net_prio/nfs_high/net_prio.ifpriomap

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7. Start the nfs and smb services and check whether their processes have been moved into the correct cgroups:

   ~]# systemctl start smb
   Starting SMB services:                                     [  OK  ]
   ~]# cat /sys/fs/cgroup/net_prio/samba_low/tasks
   16122
   16124
   ~]# systemctl start nfs
   Starting NFS services:                                     [  OK  ]
   Starting NFS quotas:                                       [  OK  ]
   Starting NFS mountd:                                       [  OK  ]
   Stopping RPC idmapd:                                       [  OK  ]
   Starting RPC idmapd:                                       [  OK  ]
   Starting NFS daemon:                                       [  OK  ]
   ~]# cat sys/fs/cgroup/net_prio/nfs_high/tasks
   16321
   16325
   16376
   

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   Network traffic originating from NFS now has higher priority than traffic originating from Samba.