An overview of Solaris Zones is available in blog entry: Zone creation for dummies. It is possible to limit the resource utilization in each zone, with Solaris containers. Detailed information about the kind of resources that can be controlled, can be found in the Resource Controls chapter of Solaris Containers-Resource Management and Solaris Zones guide. The primary focus of this blog entry is to show how to restrict one of the zones to use a maximum of 3 CPUs, on a 4 CPU Sun server.

Let's assume that we have a server configured to run 3 zones (1 global + 2 local), as shown below:

 % zoneadm list -cv
   ID NAME             STATUS         PATH
    0 global           running        /
   19 v1280appserv     running        /zones/z1
   22 v1280webserv     running        /zones/z2

The assumption is that the application server running in v1280appserv zone is going to consume majority of CPU cycles. So to give a fair chance to run web server, and other applications on this server, let's try to restrict the non-global zone, v1280appserv, to use a maximum of 3 processors only, leaving one processor for the web server. This was shown in the following figure:


Steps for CPU resource control

1. Enable pools facility

Make sure the resource pool daemon, poold, is running.

 % ps -eaf | grep poold
     root 20019 18948   0 15:03:58 pts/3       0:00 grep poold

 % pooladm
 pooladm: couldn't open pools state file: Facility is not active

Use -e option of pooladm to enable the pools facility

 % pooladm -e
 % pgrep poold
 18951

Without any options, pooladm prints out the currently running pools configuration

 % pooladm
 system sdcv1280s001
         string  system.comment
         int     system.version 1
         boolean system.bind-default true
         int     system.poold.pid 18951

         pool pool_default
                 int     pool.sys_id 0
                 boolean pool.active true
                 boolean pool.default true
                 int     pool.importance 1
                 string  pool.comment
                 pset    pset_default

         pset pset_default
                 int     pset.sys_id -1
                 boolean pset.default true
                 uint    pset.min 1
                 uint    pset.max 65536
                 string  pset.units population
                 uint    pset.load 17
                 uint    pset.size 4
                 string  pset.comment

                 cpu
                         int     cpu.sys_id 1
                         string  cpu.comment
                         string  cpu.status on-line

                 cpu
                         int     cpu.sys_id 0
                         string  cpu.comment
                         string  cpu.status on-line

                 cpu
                         int     cpu.sys_id 3
                         string  cpu.comment
                         string  cpu.status on-line

                 cpu
                         int     cpu.sys_id 2
                         string  cpu.comment
                         string  cpu.status on-line

2. Configure & load pool into memory

Since the plan is to restrict v1280appserv zone to 3 processors, create an input file as shown below. This file will be used to configure the required resource pool using poolcfg.

 % cat zonepoolcfg
 create pset appserv-pset  ( uint pset.min = 3; uint pset.max = 3 )
 create pool appserv-pool
 associate pool appserv-pool ( pset appserv-pset )

create pset appserv-pset ( uint pset.min = 3; uint pset.max = 3 ) creates a processor set with 3 processors
create pool appserv-pool creates a new pool called appserv-pool
associate pool appserv-pool ( pset appserv-pset ) associates the processor set appserv-pset with pool appserv-pool

Update the configuration using the zonepoolcfg input file.

 % poolcfg -f zonepoolcfg
 poolcfg: cannot load configuration from /etc/pooladm.conf: No such file or directory

Note that /etc/pooladm.conf file must exist before updating it. Use -s option of pooladm to save active configuration from memory in to /etc/pooladm.conf

 % pooladm -s
 % ls -l /etc/pooladm.conf
 -rw-rw-r--   1 root     root        1429 Feb 28 13:43 /etc/pooladm.conf

Now since the /etc/pooladm.conf exists, update it with the new pool configuration that we just created. This can be done with -f option of poolcfg -- it takes the input file as an argument.

 % poolcfg -f zonepoolcfg

Alternatively you can run the following commands instead of an input file, to update the configuration:

 % poolcfg -c 'create pset appserv-pset  ( uint pset.min = 3; uint pset.max = 3 )'
 % poolcfg -c 'create pool appserv-pool'
 % poolcfg -c 'associate pool appserv-pool ( pset appserv-pset )'

Next step is to instantiate (ie., activate) the configuration from /etc/pooladm.conf in to memory -- use -c option of pooladm to do this. It takes a file name as an argument; but if no file name is specified, it will read the configuration from /etc/pooladm.conf

 % pooladm -c
 % psrset
 user processor set 1: processors 0 1 2

Observe that one processor set is created with 3 processors in that set.

Check the current pool configuration one more time, with pooladm.

 % pooladm
 system sdcv1280s001
         string  system.comment
         int     system.version 1
         boolean system.bind-default true
         int     system.poold.pid 18951

         pool appserv-pool
                 int     pool.sys_id 1
                 boolean pool.active true
                 boolean pool.default false
                 int     pool.importance 1
                 string  pool.comment
                 pset    appserv-pset
 
  ...
  ...

         pset appserv-pset
                 int     pset.sys_id 1
                 boolean pset.default false
                 uint    pset.min 3
                 uint    pset.max 3
                 string  pset.units population
                 uint    pset.load 0
                 uint    pset.size 3
                 string  pset.comment

                 cpu
                         int     cpu.sys_id 1
                         string  cpu.comment
                         string  cpu.status on-line

                 cpu
                         int     cpu.sys_id 0
                         string  cpu.comment
                         string  cpu.status on-line

                 cpu
                         int     cpu.sys_id 2
                         string  cpu.comment
                         string  cpu.status on-line

  ...
  ...

3. Configure the zone(s)

Since the v1280appserv zone is already created, we just need to connect the zone to the pool that we just created. Use zonecfg to update the zone configuration.

 % zonecfg -z v1280appserv
 zonecfg:v1280appserv> set pool=appserv-pool
 zonecfg:v1280appserv> verify
 zonecfg:v1280appserv> exit

If the zone is not created yet, follow the instructions of Zone creation for dummies, and specify the pool, when the zone is configured.

4. Reboot the zone

Simply reboot the zone, v1280appserv, so it binds to the newly created pool, when it comes back.

 % zlogin v1280appserv init 6
 % zoneadm list -cv
   ID NAME             STATUS         PATH
    0 global           running        /
   19 v1280appserv     shutting_down  /zones/z1
   22 v1280webserv     running        /zones/z2

 % zoneadm list -cv
   ID NAME             STATUS         PATH
   ...
   23 v1280appserv     ready          /zones/z1

 % zoneadm list -cv
   ID NAME             STATUS         PATH
   ...
   23 v1280appserv     running        /zones/z1

5. Connect & verify the resource utilization

 v1280appserv zone:

 v1280appserv:/% psrset
 user processor set 1: processors 0 1 2

 v1280appserv:/% psrinfo
 0       on-line   since 01/19/2006 13:44:11
 1       on-line   since 01/19/2006 13:44:12
 2       on-line   since 01/19/2006 13:44:12

 v1280appserv:/%vmstat 2
  kthr      memory            page            disk          faults      cpu
  r b w   swap  free  re  mf pi po fr de sr s0 s1 s3 --   in   sy   cs us sy id
  0 0 0 16964480 6000376 3 6  8  5  4  0  0  1  0  0  0  342  293  240  4  1 96
  0 0 0 15999272 5119352 0 25 4  0  0  0  0  0  2  0  0  875 2948  968 62  2 36
  0 0 0 15994448 5114792 23 105 0 0 0  0  0 13  2  0  0  620 1666  433 51  1 48
  0 0 0 15982504 5102680 33 182 0 0 0  0  0  0  6  0  0  702 2246  767 49  2 50
  0 0 0 15976104 5096336 0 14 0  0  0  0  0  0  0  0  0  575 1376  461 32  1 67
  0 0 0 15969896 5090152 0 8  0  0  0  0  0  0  0  0  0  472 1067  569 18  1 82
  0 0 0 15963296 5083672 0 38 0  0  0  0  0  0  0  0  0  685 2440  731 38  2 60

 v1280webserv zone:

 v1280webserv:/% psrset
 v1280webserv:/% psrinfo
 3       on-line   since 01/19/2006 13:44:12

 v1280webserv:/%vmstat 2
  kthr      memory            page            disk          faults      cpu
  r b w   swap  free  re  mf pi po fr de sr s0 s1 s3 --   in   sy   cs us sy id
  0 0 0 16964480 6000376 1 2  4  0  0  0  0  1  0  0  0   22  110  102  4  1 95
  0 0 0 16032976 5152368 0 21 8  0  0  0  0  0  1  0  0   99 1013 1239 13  4 83
  0 0 0 16024560 5143968 0 1  0  0  0  0  0  0  2  0  0   69  915  816 12  3 85
  0 0 0 16022272 5141744 0 1  0  0  0  0  0  0  2  0  0   41  738  715  7  2 90
  0 0 0 16011216 5130992 0 7  0  0  0  0  0  0  3  0  0   92  936  976 11  4 85
  0 0 0 16004560 5124480 0 4  0  0  0  0  0  0  3  0  0   44  768  726  6  2 92
  0 0 0 15999272 5119352 0 1  0  0  0  0  0  0  2  0  0  132 1196 1387 19  4 76

 Global Zone:

    PID USERNAME  SIZE   RSS STATE  PRI NICE      TIME  CPU PROCESS/NLWP
  19844 giri     1007M  908M cpu2    59    0   0:04:49  16% siebmtshmw/154
  19859 giri     1007M  908M sleep   59    0   0:04:48  16% siebmtshmw/141
  19870 giri      999M  900M cpu0    59    0   0:04:38  16% siebmtshmw/145
  19906 giri      291M  127M run     29   10   0:01:27 4.3% webservd/417
  19907 giri      249M   85M run     59    0   0:00:22 1.2% webservd/158
  19976 giri      103M   63M sleep   32    0   0:00:01 1.1% siebmtshmw/7

 ZONEID    NPROC  SIZE   RSS MEMORY      TIME  CPU ZONE
     23       54 4382M 3626M    45%   0:15:59  50% v1280appserv
     22       40  771M  320M   4.0%   0:05:40 5.5% v1280webserv
      0       37  355M   80M   1.0%   1:02:45 0.2% global

It is that simple.

Troubleshooting:

If you encounter the following error, double check your configuration.
        pooladm: configuration at '/etc/pooladm.conf' cannot be instantiated on current system
It is very likely that you configured some resource that is either not available or beyond its limits, on the system.

For more examples, see:

1. [URL updated 05/28/08] Brendan Gregg's Zones documentation
   
2. Sun's HOW-TO Guide: Solaris Containers: Consolidating Servers and Applications

Technorati tags
Solaris | OpenSolaris | Zones | Containers