All New Zonestat!

Part 1

Recently I gave a brief overview of the enhancements available in Solaris 11 Express. I also hinted at more blog entries, mostly featuring Solaris Zones and network virtualization.

Before experimenting with new functions it's useful to have some tools to measure the results. With that in mind, this blog entry and its successor(s) will discuss new measurement tools that are in Solaris 11 Express: zonestat(1), flowstat(1M) and dlstat(1M). I will start with zonestat.

Zonestat Introduction

But first some history. For Solaris 10 I created an open-source tool I named "zonestat". That tool filled a need: one integrated view of the resource consumption and optional resource control settings of all running zones. The resources listed included CPUs, physical memory, virtual memory, and locked memory. Zonestat provided a "dashboard" that greatly eased the task of monitoring the resource usage of Solaris Zones.

That tool has these main drawbacks:

  1. It's written in Perl and uses a large set of existing Solaris commands to gather all of the data that it needs. Executing all of those commands for each data sample uses a significant amount of CPU time.
  2. It is a separate tool, not part of Solaris. It is not supported.
  3. It was originally intended as a prototype, a demonstration of what could be accomplished. I made a number of enhancements along the way, but for a while it wasn't clear whether it made sense to upgrade it for Solaris 11.
However, even with those shortcomings, that zonestat script was put into production at a number of data centers.

In 2009 Solaris Engineering decided to write a fully supported version of zonestat, as a new Solaris command. Instead of someone writing code in his spare time (me), a member of the Solaris Zones Engineering Team (Steve Lawrence) was assigned to write a comprehensive, efficient, fully featured tool that achieved many of the same goals as the original zonestat, and many more. Using the experience gained from the original zonestat script, a completely new program (also called "zonestat") had the potential to solve all of the problems of the open-source Perl script, and add new features which had been requested by users of Solaris Zones, and other features which the Zones Engineering Team knew would be useful.

And in Solaris 11 Express that potential was realized. Because the new zonestat performs almost all of the functions of the original zonestat script, and performs far more in addition, the rest of this blog entry (and the next one) will only discuss the new zonestat which is part of Solaris 11 Express.

The new zonestat(1) command has a plethora of options. These options allow the user to list data:

  • for each of the system's zones, including the global zone and data specific to kernel processing but not directly attributable to any one zone
  • for any subset of zones
  • regarding one or more types of resources, in absolute units or as a portion of available or capped resources
  • regarding one or more instances of resources (e.g. a particular processor set)
  • that has been sorted by one or more output columns
  • that is human-readable output or output that can be easily parsed by a script or other program
  • that includes timestamps, in one of several formats
  • that includes regular aggregations (called "summary reports"), such as "highest value during the interval" or "average value during the interval"
Zonestat has a variety of uses. The most obvious is monitoring resource usage of zones. Even if you don't use resource controls, zonestat will help you by telling you when a zone is using a significant portion (or all!) of the system's resources. Of course, zonestat really brings value to systems that are using resource controls, making it easy to determine which zones are near their caps - a sure sign that there is a problem with that zone's workload or that the zone's cap is too low.

In addition, you can use zonestat to determine proper values for resource controls. For example, you can deploy a workload in a zone and use zonestat to determine the maximum amount of CPU capacity it uses. That information will enable you to make better decisions about how many CPUs to assign to that zone - if you have decided that the workload should use its own, dedicated CPUs to the zone.

If you are not familiar with the resource management controls offered by Solaris, you may wish to view the relevant documentation before, during or after reading the rest of this. The book "Oracle Solaris 10 System Virtualization Essentials" also describes all of the resource controls available for Solaris 10 Zones, and how they can be used to achieve various goals. Finally, the document "Understanding the Security Capabilities of Solaris" approaches the same content from a security perspective.

Now let's explore some of the interesting things you can do with zonestat.

Basics

The default output provides the data you would expect - basic information about the resource usage of all zones on the system. The command syntax can be simplified to this (omitting some features for now):

zonestat [options] interval [duration]
and the basic output looks like this:
GZ$ zonestat 5 2
Collecting data for first interval...
Interval: 1, Duration: 0:00:05
SUMMARY                  Cpus/Online: 32/32   Physical: 31.8G    Virtual: 47.8G
                    ----------CPU---------- ----PHYSICAL----- -----VIRTUAL-----
               ZONE  USED %PART  %CAP %SHRU  USED   PCT  %CAP  USED   PCT  %CAP
            [total]  0.10 0.31%     -     - 3109M 9.52%     - 7379M 15.0%     -
           [system]  0.01 0.04%     -     - 2797M 8.57%     - 7115M 14.5%     -
             global  0.08 0.51%     -     -  141M 0.43%     -  129M 0.26%     -
              zoneA  0.00 0.02%     -     - 43.7M 0.13%     - 35.4M 0.07%     -
              zoneB  0.00 0.02%     -     - 42.0M 0.12%     - 32.8M 0.06%     -
              zoneC  0.00 0.04%     -     - 42.0M 0.12%     - 32.8M 0.06%     -
              zoneD  0.00 0.02%     -     - 42.1M 0.12%     - 33.2M 0.06%     -

Interval: 2, Duration: 0:00:10
SUMMARY                  Cpus/Online: 32/32   Physical: 31.8G    Virtual: 47.8G
                    ----------CPU---------- ----PHYSICAL----- -----VIRTUAL-----
               ZONE  USED %PART  %CAP %SHRU  USED   PCT  %CAP  USED   PCT  %CAP
            [total]  0.09 0.30%     -     - 3109M 9.52%     - 7379M 15.0%     -
           [system]  0.01 0.03%     -     - 2797M 8.57%     - 7115M 14.5%     -
             global  0.08 0.51%     -     -  142M 0.43%     -  129M 0.26%     -
              zoneA  0.00 0.02%     -     - 43.7M 0.13%     - 35.4M 0.07%     -
              zoneB  0.00 0.02%     -     - 42.0M 0.12%     - 32.8M 0.06%     -
              zoneC  0.00 0.02%     -     - 42.0M 0.12%     - 32.8M 0.06%     -
              zoneD  0.00 0.02%     -     - 42.1M 0.12%     - 33.2M 0.06%     -

First, note that unlike other Solaris stat tools (e.g. vmstat) the first set of data is not a summary since the system booted. Instead, zonestat pauses for the time interval specified on the command line, at which point it displays data representing the first sample. (Zonestat doesn't actually collect the data. Its companion, zonestatd(1M) performs that service for all zonestat clients.)

Also, you probably noticed those two special lines, "[total]" and "[system]". The first of those indicates data about the total quantity of each resource, across the whole system. The lines labeled "[system]" show resource consumption by the kernel or by processes that aren't associated with any one zone.

Zonestat can produce a great deal of information - more than will fit on one line. Its various options allow you to view summary data - as provided in the default - or to focus on a zone, or on a particular type or instance of a resource, or a combination of those. Obviously, the header will be tailored to the output requested.

The summary header looks like this:

Interval: 1, Duration: 0:00:05
SUMMARY                  Cpus/Online: 32/32   Physical: 31.8G    Virtual: 47.8G
                    ----------CPU---------- ----PHYSICAL----- -----VIRTUAL-----
               ZONE  USED %PART  %CAP %SHRU  USED   PCT  %CAP  USED   PCT  %CAP
The first line of data, per sample, tells you the ordinal number of the sample - not very useful if you're just checking a few seconds of data, but pretty helpful when you're scanning through 3 days worth of output. The Duration field is similar, but is a measurement of time since the command began.

The SUMMARY line shows the quantity of CPUs that exist in the system and how many of them are online. (I wrote an earlier blog entry about the method that Solaris uses to count CPUs.) That line also shows the system's amount of RAM ("Physical") and Virtual Memory (the size of RAM plus swap space on disk).

The ZONE column contains the name of the zone. The values in that row represent that zone's use of resources. The columns labeled USED show that zone's consumption of each resource. The unit depends on the resource. For CPUs, a value of 1 represents a "Solaris CPU." For memory, the unit is specified in the output.

Besides those generic header elements, some are specific to a resource type. %PART shows the CPU utilization, as a percentage of the compute capacity of the processor set in which the zone's processes run. %CAP is the percentage of the zone's CPU cap which has been used recently (if a cap has been applied to the zone). %SHRU indicates the amount of CPU used as a percentage of the shares assigned to the zone (if the Fair Share Scheduler is in use and shares have been assigned to this zone). The latter may occasionally show a surprising result: a value greater than 100%. I don't have space here to explain the Fair Share Scheduler, but the short version is "FSS enforces a minimum amount of available CPU capicity if there is contention for the CPUs, but it does not enforce a maximum. If there isn't contention, any process which wants to consume CPU cycles can do so - which can lead to a value greater than 100%."

The PHYSICAL section shows the amount of RAM used, the portion of the system's memory (PCT) represented by that amount of RAM, and the portion of the zone's RAM cap, if one has been set. The VIRTUAL section has similar fields.

Comparing Usage to Caps

To show the data you might see when a zone has a RAM cap, let's set one. We could do this in zonecfg(1M) for the next time the zone boots, but I don't feel like rebooting the zone, so let's add that cap while the zone runs. First, a quick check of the resource capping daemon. (In these examples, I am logged in as a user which is configured to use non-default administrative privileges. To temporarily gain those privileges, I will use the pfexec(1) command.)
GZ$ svcs rcap
STATE          STIME    FMRI
online         Oct_28   svc:/system/rcap:default
The service is online, and the cap is easy to set:
GZ$ pfexec rcapadm -z zoneB -m 512m
GZ$ zonestat -z zoneB 10 1
Collecting data for first interval...
Interval: 1, Duration: 0:00:10
SUMMARY                  Cpus/Online: 32/32   Physical: 31.8G    Virtual: 47.8G
                    ----------CPU---------- ----PHYSICAL----- -----VIRTUAL-----
               ZONE  USED %PART  %CAP %SHRU  USED   PCT  %CAP  USED   PCT  %CAP
            [total]  0.15 0.49%     -     - 3112M 9.53%     - 7382M 15.0%     -
           [system]  0.01 0.05%     -     - 2797M 8.57%     - 7115M 14.5%     -
              zoneB  0.00 0.10%     -     - 42.5M 0.13% 8.31% 33.3M 0.06%     -

ZoneB is using 42.5MB, which is 0.13% of the system's memory (31.8GB), and 8.31% of the 512MB cap that we set.

One of the many very useful abilities of zonestat is its ability to focus on a small part of the data which it can potentially display. The previous example demonstrated its ability to limit the output to one zone. We can also limit the output to just one resource type, or "zoom in" further to one instance of a resource.

Let's limit our view to the RAM used by that zone:

GZ$ zonestat -r physical-memory -z zoneB 10 1
Collecting data for first interval...
Interval: 1, Duration: 0:00:10
PHYSICAL-MEMORY              SYSTEM MEMORY
mem_default                          31.8G
                                ZONE  USED   PCT   CAP  %CAP
                             [total] 3113M 9.53%     -     -
                            [system] 2797M 8.56%     -     -
                               zoneB 42.5M 0.13%  512M 8.31%
We can "zoom out" and look at all of the processor sets and their zone assignments (something that was difficult in Solaris 10):
GZ$ pfexec zoneadm -z zoneA boot
GZ$ pfexec zoneadm -z zoneC boot
GZ$ pfexec zoneadm -z zoneD boot
GZ$ pfexec zonestat -r psets 10 1
Collecting data for first interval...
Interval: 1, Duration: 0:00:10
PROCESSOR_SET                   TYPE  ONLINE/CPUS     MIN/MAX
pset_default            default-pset        16/16         1/-
                                ZONE  USED   PCT   CAP  %CAP   SHRS  %SHR %SHRU
                             [total]  0.17 1.10%     -     -      -     -     -
                            [system]  0.03 0.23%     -     -      -     -     -
                              global  0.13 0.86%     -     -      -     -     -

PROCESSOR_SET                   TYPE  ONLINE/CPUS     MIN/MAX
zoneD                  dedicated-cpu          4/4         4/4
                                ZONE  USED   PCT   CAP  %CAP   SHRS  %SHR %SHRU
                             [total]  1.10 27.6%     -     -      -     -     -
                            [system]  0.00 0.00%     -     -      -     -     -
                               zoneD  1.10 27.6%     -     -      -     -     -

PROCESSOR_SET                   TYPE  ONLINE/CPUS     MIN/MAX
zoneC                  dedicated-cpu          4/4         4/4
                                ZONE  USED   PCT   CAP  %CAP   SHRS  %SHR %SHRU
                             [total]  1.00 25.0%     -     -      -     -     -
                            [system]  0.08 2.00%     -     -      -     -     -
                               zoneC  0.92 23.0%     -     -      -     -     -

PROCESSOR_SET                   TYPE  ONLINE/CPUS     MIN/MAX
zoneB                  dedicated-cpu          4/4         4/4
                                ZONE  USED   PCT   CAP  %CAP   SHRS  %SHR %SHRU
                             [total]  0.00 0.14%     -     -      -     -     -
                            [system]  0.00 0.00%     -     -      -     -     -
                               zoneB  0.00 0.14%     -     -      -     -     -

PROCESSOR_SET                   TYPE  ONLINE/CPUS     MIN/MAX
zoneA                  dedicated-cpu          4/4         4/4
                                ZONE  USED   PCT   CAP  %CAP   SHRS  %SHR %SHRU
                             [total]  0.00 0.14%     -     -      -     -     -
                            [system]  0.00 0.00%     -     -      -     -     -
                               zoneA  0.00 0.14%     -     -      -     -     -


With the basics out of the way, next time I will discuss some other options that display other data and organize the output in different ways.

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Comments:

Jeff, this is great stuff -- thanks for demonstrating. I very much look forward to having more comprehensive per-zone statistics.

My first question: Does zonestatd(1M) retain all of the data, or does it only collect when somebody is looking with zonestat(1)?

On my hosts, I would like to keep all of the raw telemetry, and run reports against it -- something analogous to "sar -f <file> -s <time> -e <time>".

I looked at the manpages, but couldn't tell if this sort of reporting capability is there. Perhaps this is done through extended accounting tools?

Thx... -c

Posted by Craig S. Bell on December 07, 2010 at 07:29 AM EST #

zonestatd only collects data when a zonestat command is running.

We would certainly like to extend zonestatd to allow data to be logged in a historical format, and add new sar-like options to re-run the data through the zonestat command. Would you find it sufficient to be able to replay the data through zonestat, or would you want a stable history-file format as well, to interrogate directly?

As always, see Oracle's "future looking statements" disclosures.

Currently, you can run zonestat -P to save the data in a ":" delimited format, which is a lot easer to parse for post-analysis.

Posted by Stephen Lawrence on December 07, 2010 at 07:49 AM EST #

Stephen, Using zonestat(1) to read from logged data would be sufficient for my needs. Thx. -c

Posted by Craig S. Bell on December 07, 2010 at 08:40 AM EST #

What about exposing zone metrics via SNMP? that's something I've always wanted to do on Sol10 for things like graphing per-zone CPU and memory consumption. I suppose one could write a MIB that executes zonestat under the covers, but a few ketats wouldn't go amiss...

Posted by Danny on December 07, 2010 at 12:37 PM EST #

That should say kstats obviously...

Posted by Danny on December 07, 2010 at 12:38 PM EST #

Pleasepleaseprettyplease do a backport to Sol10! We (and for sure lots of others) will be using Sol10 for a while, even after Sol11 arrives, and a zonestat should have been there from the beginning!

Posted by fese on February 03, 2011 at 03:50 AM EST #

Fese, see the first link in the section "Zonestat Introduction" in this blog entry. That zonestat was written for Solaris 10.

Posted by Jeffrey Victor on February 03, 2011 at 01:42 PM EST #

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About

Jeff Victor writes this blog to help you understand Oracle's Solaris and virtualization technologies.

The views expressed on this blog are my own and do not necessarily reflect the views of Oracle.

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