openstack/ironic-python-agent
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ironic-python-agent/doc/source/admin/troubleshooting.rst
Arne Wiebalck b5e25760af [doc] How to pause the IPA for debugging 
This patch adds two handy methods to pause the IPA when it needs
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Troubleshooting Ironic-Python-Agent (IPA)

This document contains basic trouble shooting information for IPA.

Gaining Access to IPA on a node

In order to access a running IPA instance a user must be added or enabled on the image. Below we will cover several ways to do this.

Access via ssh

ironic-python-agent-builder

SSH access can be added to DIB built IPA images with the dynamic-login1 or the devuser element2

The dynamic-login element allows the operator to inject a SSH key when the image boots. Kernel command line parameters are used to do this.

dynamic-login element example:

  • Add sshkey="ssh-rsa BBA1..." to pxe_append_params setting in the ironic.conf file
  • Restart the ironic-conductor with the command service ironic-conductor restart

Install ironic-python-agent-builder following the guide3

devuser element example:

export DIB_DEV_USER_USERNAME=username
export DIB_DEV_USER_PWDLESS_SUDO=yes
export DIB_DEV_USER_AUTHORIZED_KEYS=$HOME/.ssh/id_rsa.pub
ironic-python-agent-builder -o /path/to/custom-ipa -e devuser debian

tinyipa

If you want to enable SSH access to the image, set AUTHORIZE_SSH variable in your shell to true before building the tinyipa image:

export AUTHORIZE_SSH=true

By default it will use default public RSA (or, if not available, DSA) key of the user running the build (~/.ssh/id_{rsa,dsa}.pub).

To provide other public SSH key, export full path to it in your shell before building tinyipa as follows:

export SSH_PUBLIC_KEY=/path/to/other/ssh/public/key

The user to use for access is default Tiny Core Linux user tc. This user has no password and has password-less sudo permissions. Installed SSH server is configured to disable Password authentication.

Access via console

If you need to use console access, passwords must be enabled there are a couple ways to enable this depending on how the IPA image was created:

ironic-python-agent-builder

Users wishing to use password access can be add the dynamic-login4 or the devuser element5

The dynamic-login element allows the operator to change the root password dynamically when the image boots. Kernel command line parameters are used to do this.

dynamic-login element example:

Generate a ENCRYPTED_PASSWORD with the openssl passwd -1 command
Add rootpwd="$ENCRYPTED_PASSWORD" value on the pxe_append_params setting in /etc/ironic/ironic.conf
Restart the ironic-conductor with the command service ironic-conductor restart

Users can also be added to DIB built IPA images with the devuser element6

Install ironic-python-agent-builder following the guide7

Example:

export DIB_DEV_USER_USERNAME=username
export DIB_DEV_USER_PWDLESS_SUDO=yes
export DIB_DEV_USER_PASSWORD=PASSWORD
ironic-python-agent-builder -o /path/to/custom-ipa -e devuser debian

tinyipa

The image built with scripts provided in tinyipa folder of Ironic Python Agent Builder repository by default auto-logins the default Tiny Core Linux user tc to the console. This user has no password and has password-less sudo permissions.

How to pause the IPA for debugging

When debugging issues with the IPA, in particular with cleaning, it may be necessary to log in to the RAM disk before the IPA actually starts (and delay the launch of the IPA). One easy way to do this is to set maintenance on the node and then trigger cleaning. Ironic will boot the node into the RAM disk, but the IPA will stall until the maintenance state is removed. This opens a time window to log into the node.

Another way to do this is to add simple cleaning steps in a custom hardware manager which sleep until a certain condition is met, e.g. until a given file exists. Having multiple of these "barrier steps" allows to go through the cleaning steps and have a break point in between them.

Set IPA to debug logging

Debug logging can be enabled a several different ways. The easiest way is to add ipa-debug=1 to the kernel command line. To do this:

  • Append ipa-debug=1 to the pxe_append_params setting in the ironic.conf file
  • Restart the ironic-conductor with the command service ironic-conductor restart

If the system is running and uses systemd then editing the services file will be required.

  • systemctl edit ironic-python-agent.service
  • Append --debug to end of the ExecStart command
  • Restart IPA. See the Manually restart IPA section below.

Where can I find the IPA logs

Retrieving the IPA logs will differ depending on which base image was used.

  • Operating system that do not use systemd (ie Ubuntu 14.04)
    • logs will be found in the /var/log/ folder.
  • Operating system that do use systemd (ie Fedora, CentOS, RHEL)
    • logs may be viewed with sudo journalctl -u ironic-python-agent

Manually restart IPA

In some cases it is helpful to enable debug mode on a running node. If the system does not use systemd then IPA can be restarted directly:

sudo /usr/local/bin/ironic-python-agent [--debug]

If the system uses systemd then systemctl can be used to restart the service:

sudo systemctl restart ironic-python-agent.service

References

  1. `Dynamic-login DIB element`: https://github.com/openstack/diskimage-builder/tree/master/diskimage_builder/elements/dynamic-login↩︎

  2. `DevUser DIB element`: https://github.com/openstack/diskimage-builder/tree/master/diskimage_builder/elements/devuser↩︎

  3. `ironic-python-agent-builder`: https://docs.openstack.org/ironic-python-agent-builder/latest/install/index.html↩︎

  4. `Dynamic-login DIB element`: https://github.com/openstack/diskimage-builder/tree/master/diskimage_builder/elements/dynamic-login↩︎

  5. `DevUser DIB element`: https://github.com/openstack/diskimage-builder/tree/master/diskimage_builder/elements/devuser↩︎

  6. `DevUser DIB element`: https://github.com/openstack/diskimage-builder/tree/master/diskimage_builder/elements/devuser↩︎

  7. `ironic-python-agent-builder`: https://docs.openstack.org/ironic-python-agent-builder/latest/install/index.html↩︎