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# You can SSH successfully into your FCOS system.
# You can SSH successfully into your FCOS system and that it is on the expected version
 
$ ssh 172.25.81.173
Fedora CoreOS 36.20220325.1.0
Tracker: https://github.com/coreos/fedora-coreos-tracker
Discuss: https://discussion.fedoraproject.org/tag/coreos
 
Last login: Mon Apr  4 14:42:45 2022 from 156.111.209.231
[core@d-zram-test-1 ~]$
</pre>
# Verify the zram configuration injected by ignition is as expected.
 
<pre>$ cat /etc/systemd/zram-generator.conf
# This config file enables a /dev/zram0 device with the default settings
[zram0]
</pre>
 
# Verify zram has been correctly defined as a swap partition and to the expected size
<pre>[core@d-zram-test-1 ~]$ zramctl --output-all
zramctl --output-all
NAME      DISKSIZE DATA COMPR ALGORITHM STREAMS ZERO-PAGES TOTAL MEM-LIMIT MEM-USED MIGRATED MOUNTPOINT
/dev/zram0      4G  4K  80B lzo-rle        4          0  12K        0B      12K      0B [SWAP]
[core@d-zram-test-1 ~]$ swapon
NAME      TYPE      SIZE USED PRIO
/dev/zram0 partition  4G  0B  100
</pre>
 
# Saturate memory and confirm usage via zramctl
 
In the example below we have a 16GB machine.  We initially fill memory with 15GB and confirm usage via top.  Then add another 3GB of usage and confirm that zram is used.
 
</p>
</dev/zero head -c 15G | tail &
[1] 1810
[core@d-zram-test-1 ~]$ sleep 5
[core@d-zram-test-1 ~]$ top -o %MEM -bn1 | head -n 15
top - 14:50:20 up 14 min,  1 user,  load average: 0.60, 0.24, 0.12
Tasks: 125 total,  3 running, 122 sleeping,  0 stopped,  0 zombie
%Cpu(s):  1.6 us,  1.6 sy,  0.0 ni, 95.2 id,  0.0 wa,  0.0 hi,  0.0 si,  1.6 st
MiB Mem :  15994.1 total,    238.0 free,  15687.3 used,    68.9 buff/cache
MiB Swap:  4096.0 total,  4068.9 free,    27.1 used.    109.9 avail Mem
 
    PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM    TIME+ COMMAND
  1810 core      20  0  15.1g  15.1g  1668 R  6.2  96.4  0:15.48 tail
  1466 root      20  0 1440984  15588  3844 S  0.0  0.1  0:00.27 dockerd
  1475 root      20  0 1345832  14856  2416 S  0.0  0.1  0:01.83 containerd
    773 root      20  0  58856  10444  9236 S  0.0  0.1  0:00.46 systemd-journal
  1513 root      20  0  770212  6928      0 S  0.0  0.0  0:00.16 docker-driver
    848 systemd+  20  0  23984  6688  3256 S  0.0  0.0  0:00.14 systemd-resolve
      1 root      20  0  172348  5396    848 S  0.0  0.0  0:03.69 systemd
  1759 core      20  0  19240  4480  1348 R  12.5  0.0  0:06.30 sshd
[core@d-zram-test-1 ~]$ </dev/zero head -c 3G | tail &
[2] 1815
[core@d-zram-test-1 ~]$ top -o %MEM -bn1 | head -n 15
top - 14:50:36 up 14 min,  1 user,  load average: 0.65, 0.27, 0.14
Tasks: 126 total,  1 running, 125 sleeping,  0 stopped,  0 zombie
%Cpu(s):  1.5 us,  3.1 sy,  0.0 ni, 95.4 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
MiB Mem :  15994.1 total,    189.2 free,  15760.8 used,    44.1 buff/cache
MiB Swap:  4096.0 total,  1050.6 free,  3045.3 used.    48.7 avail Mem
 
    PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM    TIME+ COMMAND
  1810 core      20  0  15.1g  12.1g    280 S  6.2  77.7  0:15.87 tail
  1815 core      20  0 3162560  3.0g    264 S  6.2  19.3  0:03.57 tail
  1466 root      20  0 1440984  10548      0 S  0.0  0.1  0:00.27 dockerd
  1475 root      20  0 1345832  9648  2888 S  0.0  0.1  0:01.87 containerd
  1513 root      20  0  770212  6172      0 S  0.0  0.0  0:00.17 docker-driver
  1816 core      20  0    7856  3624  2996 R  0.0  0.0  0:00.00 top
      1 root      20  0  172348  2868      0 S  0.0  0.0  0:03.69 systemd
  1760 core      20  0    6212  2004  1644 S  0.0  0.0  0:00.55 bash
[core@d-zram-test-1 ~]$ zramctl --output-all
NAME      DISKSIZE DATA COMPR ALGORITHM STREAMS ZERO-PAGES TOTAL MEM-LIMIT MEM-USED MIGRATED MOUNTPOINT
/dev/zram0      4G  3G 35.6M lzo-rle        4    381047 43.4M        0B    47.4M      57B [SWAP]
[core@d-zram-test-1 ~]$ swapon
NAME      TYPE      SIZE USED PRIO
/dev/zram0 partition  4G  3G  100
</p>
 
 
# Verify the swap device is set up by viewing the swapon --show output. You can also view the true compression ratio of the currently configured zram devices by running zramctl.
# Verify the swap device is set up by viewing the swapon --show output. You can also view the true compression ratio of the currently configured zram devices by running zramctl.
# The linked documentation makes sense, nothing is obviously missing, and the instructions are clear.
# The linked documentation makes sense, nothing is obviously missing, and the instructions are clear.

Revision as of 14:53, 4 April 2022

Description

Install and validate Fedora CoreOS with swap on zram enabled

Setup

  1. Download and verify the latest FCOS next image (pick the right image for your environment).
  2. Read background on zram here.
  3. Figure out how you'd like to configure your initial zram device.
  4. Read other possible post-boot tests as described here.

How to test

  1. Create an Ignition file.
  2. Configure Zram device validating instructions here.
  3. Launch your Fedora CoreOS system using this Ignition file. See the Quickstart and the provisioning docs for a guide how to launch FCOS in most environments (bare metal, virtual, cloud, etc).

Expected Results

  1. You can SSH successfully into your FCOS system and that it is on the expected version

$ ssh 172.25.81.173 Fedora CoreOS 36.20220325.1.0 Tracker: https://github.com/coreos/fedora-coreos-tracker Discuss: https://discussion.fedoraproject.org/tag/coreos

Last login: Mon Apr 4 14:42:45 2022 from 156.111.209.231 [core@d-zram-test-1 ~]$

  1. Verify the zram configuration injected by ignition is as expected.
$ cat /etc/systemd/zram-generator.conf
# This config file enables a /dev/zram0 device with the default settings
[zram0]
  1. Verify zram has been correctly defined as a swap partition and to the expected size
[core@d-zram-test-1 ~]$ zramctl --output-all
zramctl --output-all
NAME       DISKSIZE DATA COMPR ALGORITHM STREAMS ZERO-PAGES TOTAL MEM-LIMIT MEM-USED MIGRATED MOUNTPOINT
/dev/zram0       4G   4K   80B lzo-rle         4          0   12K        0B      12K       0B [SWAP]
[core@d-zram-test-1 ~]$ swapon
NAME       TYPE      SIZE USED PRIO
/dev/zram0 partition   4G   0B  100
  1. Saturate memory and confirm usage via zramctl

In the example below we have a 16GB machine. We initially fill memory with 15GB and confirm usage via top. Then add another 3GB of usage and confirm that zram is used.

</dev/zero head -c 15G

Retrieved from "https://fedoraproject.org/w/index.php?title=QA:Testcase_swap_on_zram&oldid=639849"