[RFE] Make agent_last_heartbeat a datetime field

[Mario Villaplana]

When using an agent driver, the agent_last_heartbeat field from driver_internal_info in the nodes table in the database, which indicates the last time that an agent sent a heartbeat to ironic, is an integer indicating seconds since epoch time: https://github.com/openstack/ironic/blob/8006ec8a519fdbb34e310e785d7647ee94f68c49/ironic/drivers/modules/agent_base_vendor.py#L464

This is not consistent with other top-level ironic fields that use actual datetime fields, such as provision_updated_at.

Having a datetime field in the driver_internal_info JSON for agent_last_heartbeat would improve consistency between different fields representing timestamps, make it easier for operators to read and use the timestamps without converting them from epoch time, and make it easier for downstream tooling to use the field.

IRC discussion about this issue is here: http://eavesdrop.openstack.org/irclogs/%23openstack-ironic/%23openstack-ironic.2016-07-12.log.html#t2016-07-12T20:01:33

[Jim Rollenhagen (jim-rollenhagen)]

Going by irc discussion, this seems fine, should make a new name for it and phase it out over a cycle. Approved.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/376978

[Mario Villaplana (mario-villaplana-j)]

After some discussion, we've decided that it's better to just remove this attribute and add a release note about it, since it's completely unused by ironic and just used to log a helpful message.

discussion: http://eavesdrop.openstack.org/irclogs/%23openstack-ironic/%23openstack-ironic.2016-10-13.log.html#t2016-10-13T21:30:53

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/376978
Committed: https://git.openstack.org/cgit/openstack/ironic/commit/?id=7dc74ab75478318afc5c933472423f4c77eb662d
Submitter: Jenkins
Branch: master

commit 7dc74ab75478318afc5c933472423f4c77eb662d
Author: Mario Villaplana <email address hidden>
Date: Mon Sep 26 17:48:58 2016 +0000

    Remove "agent_last_heartbeat" internal field from agent drivers

    "agent_last_heartbeat" in the driver_internal_info dict of agent drivers is not
    used anywhere by ironic itself, except for logging purposes. This
    removes it.

    Change-Id: Ic198f6a952ed135099bcc525ef548a4aea005056
    Closes-Bug: 1602410

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: master
Review: https://review.openstack.org/387652

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/387652
Committed: https://git.openstack.org/cgit/openstack/ironic/commit/?id=128c025fc10e315df486729becdb9cd04b0c5f1e
Submitter: Jenkins
Branch: master

commit 128c025fc10e315df486729becdb9cd04b0c5f1e
Author: Ruby Loo <email address hidden>
Date: Mon Oct 17 15:37:50 2016 -0400

    Remove 'agent_last_heartbeat' from node.driver_internal_info

    node.driver_internal_info['agent_last_heartbeat'] was not being used by
    ironic, and Ic198f6a952ed135099bcc525ef548a4aea005056 removed the code
    that sets that value.

    However, for existing nodes, driver_internal_info['agent_last_heartbeat']
    may already exist, so we need to delete it. This patch does that.

    In addition, a LOG line was moved (and a nit addressed) to make the code
    a bit easier to read.

    This is a followup to Ic198f6a952ed135099bcc525ef548a4aea005056.

    Change-Id: I194d22c0e605b187823ceebae94d3ef895fb91f5
    Related-Bug: #1602410

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/ironic 7.0.0 release.