Nova should reserve some memory when sharing node with Ceph/OSD role

[Eugene Korekin]

We always have value reserved_host_memory_mb in /etc/nova/nova.conf set to 512.
We probably should reserve more memory if compute node has additional roles.
For example, Ceph/OSD hosts are recommended to have 1GB of RAM per OSD daemon instance.

As it is now Ceph can have a very negative influence on compute node performance.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/240204

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: master
Review: https://review.openstack.org/251366

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/240204
Committed: https://git.openstack.org/cgit/openstack/fuel-library/commit/?id=5199ed004c7e99ce9c847fcba2563bd57525b4cb
Submitter: Jenkins
Branch: master

commit 5199ed004c7e99ce9c847fcba2563bd57525b4cb
Author: Michael Polenchuk <email address hidden>
Date: Thu Oct 29 14:42:57 2015 +0300

    Get reserved host memory for nova-compute

    Get reserved host memory straight value for nova-compute if we have Ceph
    OSD neighbor resides on the same node.
    The formula is:
      * min default value = 512Mb
      * max value = 1.5Gb
      * straight value = 20% of total memory

    Closes-Bug: #1507306
    Change-Id: I6a58095825d248ba40d6cecd983812dd3e17abb7

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/251366
Committed: https://git.openstack.org/cgit/openstack/fuel-library/commit/?id=15564db03e60205934f8d7fa1f4bf143c9a67c06
Submitter: Jenkins
Branch: master

commit 15564db03e60205934f8d7fa1f4bf143c9a67c06
Author: Michael Polenchuk <email address hidden>
Date: Mon Nov 30 15:13:37 2015 +0300

    Align method to get value within the range

    Use min(max()) method instead of sort[1].

    Change-Id: I25e7379b92d5627a79b6f4a5f67cc77152e43480
    Related-Bug: #1507306

[Mikhail Samoylov (msamoylov)]

Steps for verification:
1. Create env
2. Add to env 1 controller, 2 compute with ceph-osd and 1 compute
3. Verify networks
4. Deploy cluster
5. On compute nodes check /etc/nova/nova.conf | grep reserved_host_memory_mb

Expected result for step 5: at least 512 Mb memory

root@node-7:~# cat /etc/nova/nova.conf | grep reserved_host_memory_mb
reserved_host_memory_mb=592

root@node-8:~# cat /etc/nova/nova.conf | grep reserved_host_memory_mb
reserved_host_memory_mb=512

root@node-6:~# cat /etc/nova/nova.conf | grep reserved_host_memory_mb
reserved_host_memory_mb=592

Verification on fuel version:
[root@nailgun ~]# cat /etc/fuel/version.yaml
VERSION:
  feature_groups:
    - mirantis
  production: "docker"
  release: "8.0"
  openstack_version: "2015.1.0-8.0"
  api: "1.0"
  build_number: "269"
  build_id: "269"
  fuel-nailgun_sha: "218e8a2ab3dc95367fa3e6de79fe506c06b7c861"
  python-fuelclient_sha: "f033192b84263f0e699458a4274289a5198ae7e4"
  fuel-agent_sha: "660c6514caa8f5fcd482f1cc4008a6028243e009"
  fuel-nailgun-agent_sha: "a33a58d378c117c0f509b0e7badc6f0910364154"
  astute_sha: "48fd58676debcc85951db68df6d77c22daa55e52"
  fuel-library_sha: "6a5f6c0afbe6a9bcd2ef40657de371ada5f966ee"
  fuel-ostf_sha: "23b7ae2a1a57de5a3e1861ffb7805394ca339cc2"
  fuel-mirror_sha: "c66309976db831a4081e5e0064028d7c67014b2f"
  fuelmenu_sha: "761685b566af981479e7e0f3c3a5eede5a40400d"
  shotgun_sha: "a0bd06508067935f2ae9be2523ed0d1717b995ce"
  network-checker_sha: "a3534f8885246afb15609c54f91d3b23d599a5b1"
  fuel-upgrade_sha: "1e894e26d4e1423a9b0d66abd6a79505f4175ff6"
  fuelmain_sha: "d4d93fec7f0c35b18c50431e8bf3eae70a6deb27"

[root@nailgun ~]# fuel node
id | status | name | cluster | ip | mac | roles | pending_roles | online | group_id
---|----------|------------------|---------|-------------|-------------------|-------------------|---------------|--------|---------
13 | discover | Untitled (c1:29) | None | 10.109.5.10 | 64:be:e6:9e:c1:29 | | | True | None
11 | discover | Untitled (d5:d9) | None | 10.109.5.6 | 64:fd:36:5d:d5:d9 | | | True | None
6 | ready | Untitled (ee:50) | 3 | 10.109.5.8 | 3e:66:af:0b:ca:bb | ceph-osd, compute | | True | 3
7 | ready | Untitled (d1:7a) | 3 | 10.109.5.4 | 3a:76:bf:0a:7c:78 | ceph-osd, compute | | True | 3
9 | ready | Untitled (24:a3) | 3 | 10.109.5.7 | 64:e1:22:f9:24:a3 | controller | | True | 3
14 | discover | Untitled (a2:6d) | None | 10.109.5.5 | 64:74:52:3b:a2:6d | | | True | None
8 | ready | Untitled (a9:08) | 3 | 10.109.5.9 | 3e:af:6f:1a:56:0c | compute | | True | 3
10 | discover | Untitled (69:34) | None | 10.109.5.11 | 64:f1:d1:9b:69:34 | | | True | None
12 | discover | Untitled (a0:c0) | None | 10.109.5.3 | 64:bc:32:c3:a0:c0 | | | True | None