Collect logs from agent ramdisk

https://bugs.launchpad.net/ironic/+bug/1587143

This spec adds support for retrieving the deployment system logs from agent ramdisk.

Problem description

Currently we do not have any documented mechanism to automatically retrieve the system logs from Bootstrap. Having access to agent ramdisk logs may be highly required especially after deployment failure. Collecting logs on remote server is common deployment thing. There are a lot of proprietary, opensource, standardized technologies that solve this task. Lets walk through linux natively supported:

  1. Syslog: is the standardized protocol for message logging, described in RFC. All distros supports syslog in different implementations rsyslogd, syslogd, syslog-ng
  2. Systemd journal-remote: systemd tool to send/receive journal messages over the network.

Proposed change

The proposed implementations is about adding documentation that helps Operators to build agent ramdisk with collecting logs feature. On top of syslog and systemd journal-remote technologies.

Changes in IPA

A new kernel parameter is added use_syslog.

  1. use_syslog (Boolean): Whether IPA should send the logs to syslog or not. Defaults to “False”.

Changes in Ironic

New pxe_append parameters are added use_syslog and syslog_server in [agent] section.

  1. use_syslog boolean): Whether IPA should send the logs to syslog or not. Defaults to “False”.
  2. syslog_server (string): IP address or DNS name of syslog server to send system logs to. Defaults to “IP address of ironic-conductor node.” The variable may be used to configure rsyslogd or syslog or any other syslog server implementation.

Changes in agent ramdisk

Bootstrap should support remote logging via syslog/systemd. All agent ramdisk changes are related to logging tool configuration (rsyslogd, syslogd, journal-remote). The logging service should be started right after networking service to make sure that we send all logs from OpenStack services. On Collector side (ironic-conductor) we receive messages from Originator (agent ramdisk) and place the according to local rules. It may be directory on the filesystem: /var/log/remote/ironic/<node_uuid>/<log_filename>

Alternatives

Implement logs collecting mechanism in Ironic and IPA as it described in https://review.openstack.org/323511

Data model impact

None

State Machine Impact

None

REST API impact

None

Client (CLI) impact

None

RPC API impact

None

Driver API impact

None

Nova driver impact

None

Ramdisk impact

Support will be added to ramdisk build tools, such as diskimage-builder and image building scripts under IPA repository to build ramdisks with remote logging support.

Security impact

None.

Other end user impact

None.

Scalability impact

None

Performance Impact

None

Other deployer impact

Deployer chooses which mechanism for collecting logs should be used. General changes to agent ramdisk described at Changes in agent ramdisk

Developer impact

None

Implementation

Assignee(s)

Primary assignee:
lucasagomes <lucasagomes@gmail.com> vsaienko <vsaienko@mirantis.com>

Other contributors:

Work Items

  • Add documentation that describes how to configure Collector on ironic-conductor, and Originator in ironic agent ramdisk on top of rsyslogd or syslogd or journal-remote.
  • Add an examples of building most popular images (coreos, tinyipa) with syslog support. New dib element will be added as well.
  • Integrate configuring Collector on devstack host.

Dependencies

None

Testing

Collecting logs from agent ramdisk will be configured on gate jobs. The directory with logs from agent ramdisk will be archived and available in the jobs artefacts.

Upgrades and Backwards Compatibility

None.

Documentation Impact

Documentation will be provided about how to configure syslog Collector to receive and store logs from Originator.

References

None.