Merge lp:~fginther/adt-cloud-worker/uci-nova-swapfile into lp:~canonical-ci-engineering/adt-cloud-worker/uci-nova

[Celso Providelo]

Add a 4GB swapfile as a way to extend available RAM.

Add a 4GB swapfile as a way to extend available RAM.

[Thomi Richards (thomir-deactivatedaccount)]

How id this better / worse / different to using the '--swap' option to 'nova boot' ?

review: Needs Information

[Thomi Richards (thomir-deactivatedaccount)]

also, don't forget to set a commit message :D

[Thomi Richards (thomir-deactivatedaccount)]

<fginther> thomi, just saw that. I'll comment in both places. --swap only works if the nova flavor is already to configured to have a swap partition.

In that case, this LGTM

review: Approve

[Francis Ginther (fginther)]

> How id this better / worse / different to using the '--swap' option to 'nova
> boot' ?

"nova --swap" requires that the nova flavor already have swap configured (this option appears to allow you to specify less then what the flavor specifies). I did try both methods on bootstack and didn't notice any functional differences. Performance may be different but a better testcase first would be helpful.

[Celso Providelo (cprov)]

Francis,

Thanks for working on this.

As discussed on IRC, it might consume few seconds on the cloud-init setup and 4 GB of disk. Since we recently bumped the disk from 10 to 50 GB, there should be no sensible side-effect on tests that do not need swap.

FTR, that is another change that has no value for core-image-testing.

review: Approve

=== modified file 'uci-nova'
--- uci-nova	2015-04-23 18:21:49 +0000
+++ uci-nova	2015-04-27 18:35:56 +0000
@@ -214,6 +214,12 @@
         archive_setup="mirror_release=\`awk '/^deb .*(debian|ubuntu)/ { print \$2,\$3; exit }' \"\$root/etc/apt/sources.list\"\`; echo \"deb \${mirror_release} main restricted universe multiverse\ndeb \${mirror_release}-updates main restricted universe multiverse\ndeb-src \${mirror_release} main restricted universe multiverse\ndeb-src \${mirror_release}-updates main restricted universe multiverse\" > /etc/apt/sources.list"
     fi
 
+    # Add a swapfile to extend the amount of RAM available to process. As this
+    # is a local file on the boot disk, it does not need any support within the
+    # nova flavor.  This does consume space on the boot disk and is not ideal
+    # from the performance perspective.
+    swap_setup="fallocate -l 4G /swapfile; chmod 600 /swapfile; mkswap /swapfile; swapon /swapfile; echo \"/swapfile none swap sw 0 0\" >> /etc/fstab"
+
     # generate cloud-init user data; mostly for manage_etc_hosts, but also get
     # rid of some unnecessary stuff in the VM
     #
@@ -234,6 +240,8 @@
  # Setup archive and do an update after changing the apt sources
  - ${archive_setup}
  - apt-get update
+ # Add a swapfile
+ - ${swap_setup}
  # Make apt faster:
  - echo 'Acquire::Languages "none";' > /etc/apt/apt.conf.d/90nolanguages
  - echo 'force-unsafe-io' > /etc/dpkg/dpkg.cfg.d/autopkgtest