Why projects? Why not?

One of the questions I often ask myself is "why aren't more sites using projects?". As I wander from forum to forum, I regularly see people saying, "I want to consolidate three [application server] instances on my system"—or two [database] instances or n applications. Many of these applications need to run with identical credentials (user id, group id, authorizations, privileges, etc.) and are only distinguishable by their working directory, environment variables, or the like. Reading these requests is a bit frustrating, as this scenario is one of the key motivations we had when introducing the project(4) database—and I can only conclude that it's my failure to really communicate its utility.

Projects let you assign a label with a specific workload. In S8 6/00 and all subsequent releases, you can explicitly launch a workload with its appropriate project using the newtask(1) command. If extended accounting has been activated using acctadm(1M) with one of the standard record groupings, then the processes within that workload will include their project ID. Writing an accounting record on every process exit can impact some workloads, so you can optionally choose to only write records when every task exits. A task is a new process collective that groups related work within a workload (so it could be a workload component, like a batch submission). acctadm(1M) will report on the current status of the extended accounting subsystem, if invoked without arguments:

$ acctadm
            Task accounting: inactive
       Task accounting file: none
     Tracked task resources: none
   Untracked task resources: extended
         Process accounting: inactive
    Process accounting file: none
  Tracked process resources: none
Untracked process resources: extended,host,mstate
            Flow accounting: inactive
       Flow accounting file: none
     Tracked flow resources: none
   Untracked flow resources: extended

The resource line is reporting what accounting resource groups and resources we can include in each record. We can expand the resource groups for each type of accounting using the -r option.

$ acctadm -r
process:
extended pid,uid,gid,cpu,time,command,tty,projid,taskid,ancpid,wait-status,zone,flag
basic    pid,uid,gid,cpu,time,command,tty,flag
task:
extended taskid,projid,cpu,time,host,mstate,anctaskid,zone
basic    taskid,projid,cpu,time
flow:
extended saddr,daddr,sport,dport,proto,dsfield,nbytes,npkts,action,ctime,lseen,projid,uid
basic    saddr,daddr,sport,dport,proto,nbytes,npkts,action

So we can enable the extended task record by invoking acctadm(1M) like

# acctadm -e extended task
# acctadm -E task
# acctadm -f /var/adm/exacct/task

In S10, you can optionally enable accounting without having it write to a file, such that the records are retrievable using getacct(2).

Of course, that's all about accounting, but projects are useful even if you're not interested in the long term resource consumption of your workloads. The project ID is useful for isolating your workload using conventional /proc-based tools like prstat(1M) and pgrep(1), as well as with DTrace. For instance to see only one's own projects, you can use the -J option to pgrep.

$ pgrep -lf -J user.sch
728069 /usr/bin/bash
728027 /usr/bin/bash
125169 /usr/bin/bash

To see workloads on the system, you can use prstat's -J option, which aggregates the activity by project ID, as well as displaying the most active processes:

$ prstat -c -J user.sch 1 1
   PID USERNAME  SIZE   RSS STATE  PRI NICE      TIME  CPU PROCESS/NLWP       
653322 xx         19M   17M cpu2     0    3 166:34:10  12% setiathome/1
911046 xx         19M   17M cpu5     0    3 170:28:53  12% setiathome/1
668697 xx         19M   17M cpu4     0    3 138:53:14  12% setiathome/1
100378 daemon   2352K 1944K sleep   60  -20  30:18:23 0.2% nfsd/5
125214 sch      4472K 4152K cpu3     1    0   0:00:00 0.0% prstat/1
100066 root     7872K 6736K sleep   29    0   2:20:42 0.0% picld/13
125169 sch      2768K 2416K sleep    1    0   0:00:00 0.0% bash/1
100156 root       91M   36M sleep   59    0   0:46:59 0.0% poold/8
100249 root     6680K 4848K sleep    1    0   8:02:46 0.0% automountd/2
100254 root     5776K 3552K sleep   59    0   0:00:01 0.0% fmd/10
100262 root     4024K 3424K sleep   59    0   0:19:40 0.0% nscd/57
100265 root     1248K  776K sleep   59    0   0:00:00 0.0% sf880drd/1
100184 root     2288K 1384K sleep    1    0   0:00:00 0.0% ypbind/1
100172 daemon   2680K 1704K sleep   58    0   1:07:32 0.0% rpcbind/1
100158 root     2216K 1336K sleep   59    0   0:00:26 0.0% in.routed/1
PROJID    NPROC  SIZE   RSS MEMORY      TIME  CPU PROJECT                     
   130        3   56M   51M   0.3% 475:56:17  37% background                  
     0       61  341M  168M   1.0%  43:21:28 0.3% system                      
 36565        4   13M   11M   0.1%   0:00:01 0.1% user.sch                    
105403       14   39M   30M   0.2%   0:00:03 0.0% user.xxxxxxx                
 77194       17   74M   62M   0.4%   0:03:10 0.0% user.xxxxxx                 
Total: 133 processes, 279 lwps, load averages: 3.07, 3.07, 3.04

(This system's pretty idle during our U.S. shutdown, so it's doing its best to find extraterrestrial customers.)

To limit your DTrace predicates to only a project of interest, use the curpsinfo built-in variable to access the pr_projid field, like

/curpsinfo->pr_projid == $projid && ..../

where I've also used the $projid scripting macro, which expands to the result of curprojid(2) for the running DTrace script. You could instead explicitly enter your project ID of interest, or use one of the argument macros if writing a script you expect to reuse.

Projects also let you place resource controls on your workload, establish its resource pool bindings, and more. We'll make it easier to use them with the forthcoming service management facility. But I'll summarize: projects are a precise and efficient way to label your workloads (as opposed to pattern matching on arguments or environment variables). If you are consolidating workloads, either because of machine eliminations, organizational mergers, or other reasons, they are definitely worth considering. If you think there's a way to make them more applicable to your work, please let me know.

Comments:

I can say for sure that I haven't been using them because I had no idea they existed until you commented on my blog about this a few days ago. I will certainly be using them now. When did this functionality sneak into solaris? I wish had known earlier, because we're now moving to seperate role accounts anyway, to better insulate the processes (weblogic instances) from each other, so I don't get to take big advantage of them (I can still come up with a few uses for them though).

Posted by Rob Meyer on July 08, 2004 at 04:40 AM PDT #

@evilrob: They quietly snuck in during Solaris 8 Update 1, but received enhancements and tie-ins (and product promotions) in Solaris 9, as part of the Solaris 9 Resource Manager. I should also mention that we have introduced Perl support for many of these interfaces as well, so you can get your project ID or read and write extended accounting files from Perl. See Sun::Solaris::{Project,Task,Exacct} for more details. (Thanks for the comment!)

Posted by Stephen on July 08, 2004 at 04:50 AM PDT #

We use a mix of Solaris 8/x86 and Solaris 8/Sparc for our production environment. Almost all of our machines are disk I/O bound, not CPU-bound, and since there is no I/O scheduler in Solaris, projects do not bring us any meaningful advantage apart from improved reporting in prstat.

Posted by Fazal Majid on July 08, 2004 at 05:57 AM PDT #

@Fazal: Good point--with CPU and memory reasonably understood, we spend a lot of time debating I/O resource management (what to observe, where to place the control, etc.). If you have ideas about what would most help your deployment or can characterize it further, please feel free to contact me.

Posted by Stephen on July 08, 2004 at 06:09 AM PDT #

My big problem with features like these is that I don't have a lot of time for trial-and-error during our normally-rushed implementations, and once something is "in the ground," we try to change as little as possible outside of security patching and the like because we're afraid to break it. That being said, I'd love to see more resources from Sun regarding "how-to" docs. For example, it would be amazing to see a document that illustrated Sun's "best practice" for setting up roles, resources and projects for consolidated application servers. I know it sounds like i'm trying to get Sun to do my work for me, and in a way, I am. I need to see examples and successes before I change the way I do things that work "pretty well" now. Being in a somewhate conservative (Fortune 100) company and always under extremely tight deadlines, I seldom have the luxury of trying things different ways more than once ;)

Posted by scott partee on September 27, 2004 at 02:55 AM PDT #

@scott: I agree; we do need to get our best practices out there and made more easily available. (Would you read a how-to document on BigAdmin? Or would you rather see them released here on blogs.sun.com?) And I appreciate the "real life" constraints of your position: conservative deployment is the rule, not the exception. But if you get a chance with a test system—and maybe a spare intern—please try to try out these features and let us know if they help. We're always listening. – Stephen

Posted by Stephen Hahn on September 27, 2004 at 04:10 AM PDT #

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