4.2. Prioritizing Network Traffic When running multiple network-related services on a single server system, it is important to define network priorities among these services. Defining the priorities ensures that packets originating from certain services have a higher priority than packets originating from other services. For example, such priorities are useful when a server system simultaneously functions as an NFS and Samba server. The NFS traffic has to be of high priority as users expect high throughput. The Samba traffic can be deprioritized to allow better performance of the NFS server. The net_prio controller can be used to set network priorities for processes in cgroups. These priorities are then translated into Type of Service (ToS) field bits and embedded into every packet. Follow the steps in Procedure 4.2, "Setting Network Priorities for File Sharing Services" to configure prioritization of two file sharing services (NFS and Samba). Procedure 4.2. Setting Network Priorities for File Sharing Services Attach the net_prio subsystem to the /cgroup/net_prio cgroup: Create two cgroups, one for each service: To automatically move the nfs services to the nfs_high cgroup, add the following line to the /etc/sysconfig/nfs file: This configuration ensures that nfs service processes are moved to the nfs_high cgroup when the nfs service is started or restarted. 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: 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. Start the cgred service to load the configuration from the step: 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: Start the nfs and smb services and check whether their processes have been moved into the correct cgroups: Network traffic originating from NFS now has higher priority than traffic originating from Samba. Similar to Procedure 4.2, "Setting Network Priorities for File Sharing Services" , the net_prio subsystem can be used to set network priorities for client applications, for example, Firefox.

Commands:
~]# mkdir sys/fs/cgroup/net_prio ~]# mount -t cgroup -o net_prio none sys/fs/cgroup/net_prio
~]# mkdir sys/fs/cgroup/net_prio/nfs_high ~]# mkdir sys/fs/cgroup/net_prio/samba_low
CGROUP_DAEMON="net_prio:nfs_high"
*:smbd net_prio samba_low
~]# systemctl start cgred Starting CGroup Rules Engine Daemon: [ OK ]
~]# 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
~]# 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