Compute Issues

Host Becomes Nonresponsive After Hardening pam.d

A KVM host becomes nonresponsive after appending the following line in the /etc/pam.d/system-auth file: 

session required pam_lastlog.so showfailed

Solution: Append the following line in the /etc/pam.d/system-auth file: 

session required pam_lastlog.so silent

The silent option does not inform you about about any previous logins; however it does update the /var/log/lastlog file.

For additional information, refer to the My Oracle Support (MOS) article Host becomes nonresponsive after hardening pam.d (Doc ID 2796734.1).

Bug: 33128719

KVM Host Under the Control of a Engine Host Can Be Accidentally Added to Another Manager Host Without Validation of Its Current State

When an KVM host is already deployed on a Manager host, you can add this KVM host to another Manager host, causing this Manager host to take the KVM host away from the original owning Manager host. Adding a KVM host that is already under the control of a Manager host is highly not recommended, but it can be done by accident. In this event, the KVM host that resides on the original owning Manager host changes to a status of Nonreponsive and all virtual machines running on it change to a status of Unknown. When you attempt to put the nonresponsive host into Maintenance mode, the following error message is generated: 
Error while executing action: Cannot switch Host to Maintenance mode.
Host still has running VMs on it and is in Non Responsive state.

Solution: For information about the workaround for this issue, refer to the related issue Removing a Stolen, Defunct, Nonresponsive, or Destroyed KVM Host .

Bug: 29127349

Duplicate KVM Host Cannot Be Moved into Maintenance Mode After Host Addition Fails

If you add a KVM host that is running virtual machines to the Manager host and you attempt to add the same KVM host using a different host name (either IP address or FQDN), the Manager host fails to add this KVM host. When you try moving the failed KVM host into Maintenance mode to remove it from the Manager, it causes the KVM host to be stuck in Preparing for Maintenance mode.

Solution: Migrate all virtual machines that are UP on the running KVM host to a different KVM host in the cluster. Doing that changes the status on the failed KVM host to Maintenance mode. You can then remove the KVM host.

Bug: 29127707

SSH Connection Hangs When Adding a New KVM Host with Firewalld Disabled to the Engine

SSH Connection hangs when adding a new KVM host with firewalld disabled to the Manager.

Solution: There is no workaround for this behavior. The SSH connection is eventually restored after some delay.

Bug: 29135914

Bridge Is Not Cleaned When Undeploying and Removing a KVM Host

After a KVM host is undeployed and removed from the Manager host, the previous bridges are not cleaned on the KVM host.

Solution: Networking resources should be manually removed or cleaned after removing the KVM host from the Manager host, and the default management network, ovirtmgmt, should not be modified. To revert any other network configurations, run the following command: 

vdsm-tool clear-nets --exclude-net ovirtmgmt

Bug: 29167000

Incomplete Error Message Stopping a KVM Host

This issue is seen with a KVM host whose Status is Unassigned. The steps to reproduce the issue are as follows:

  1. Go to Compute and then click Hosts.

  2. On the Hosts pane, click Management and from the drop-down list select Stop.

    The following incomplete Operation Canceled error message is generated: 
    Error while executing action
    Although this error message is incomplete, it is accurate; however, the message does not provide a workaround.

Solution: The Status of the KVM host must be UP before you can stop the KVM host. Try setting the KVM host to Maintenance mode and then stopping it. If this does not work, you must log in to the KVM host, resolve the issue, and bring it back up.

Bug: 29298704

Host Console Indicates KVM Host Is Registered on the Engine Host After Its Removal

The Host Console indicates that an KVM host is still registered on the Manager host after it has been removed from the Manager host. This issue is observed in the following scenario.

  1. Remove the KVM host by using the Manager as follows:
    1. On the Hosts pane, put the KVM host in Maintenance mode by clicking Management and then selecting Maintenance from the drop-down list.
    2. Click Installation and then select Reinstall from the drop-down list.
    3. Click Hosted Engine and then select Undeploy from the drop-down list.
    4. Click OK.
    5. Then set the KVM host to Maintenance mode again and click Remove to open the Remove Host(s) confirmation window and click OK.
  2. Open the Host Console.

  3. Go to Virtualization and then click Hosted Engine.

    The Host Engine Setup screen indicates that the system is already registered to the removed KVM host.

Solution: There is no workaround for this behavior.

Bug: 29444179

Removing a Stolen, Defunct, Nonresponsive, or Destroyed KVM Host

A KVM host that is under the control of a Manager host can be taken over by another Manager host. See also KVM Host Under the Control of a Engine Host Can Be Accidentally Added to Another Manager Host Without Validation of Its Current State.

For example, a KVM host that is already in use by a Manager host can be added as a New Host by a different Manager host. In this scenario, the original Manager is unable to communicate with its KVM host. Because the KVM host has a running a virtual machine, attempts to put the host into Maintenance mode are rejected with the following error message: 
Host still has running VMs on it, and is Non responsive state

Solution: There are two available methods for handling this situation:

  • Method to resolve the issue of a host being taken over by another Manager host.
  • Method to remove a KVM host that has become permanently nonfunctional.

Method to Resolve the Issue of a Host Being Taking Over by Another Engine Host

When the new Manager host takes over the KVM host, the following symptoms are observed:

  • On the original owning Manager host, the KVM host shows a status of Connecting and the virtual machines show up as running.
  • On the new Manager host, copies of the virtual machines show up as external_ vm-name and they are running.

Perform the following steps:

  1. Power off the KVM host.

    After powering off the KVM host, the following events occur:
    • The KVM host eventually goes into a status of NonResponsive on both Manager hosts .
    • The virtual machines go into a status of Unknown on both Manager hosts.
    • The following events are triggered for this KVM host on both Manager hosts: Handling non responsive Host host-name.
  2. Wait for these events to fail.

On both Manager hosts, perform the following steps:

  1. Click More Actions and select Confirm Host has been Rebooted from the drop-down list.

  2. Select the Confirm Operation checkbox and click OK.

    This action causes the virtual machines to be marked as Down on the Managers and the host to display a value of 0 under the Virtual Machines column. The virtual machines may now be migrated by the old manager to another host if that is permitted by the Migration Mode settings of the virtual machines.

  3. Set the KVM host to Maintenance mode.

Then, on the new Manager host, perform the following steps:

  1. Remove the virtual machine copies.
  2. Remove the KVM host.

When the KVM host comes back up, SSH to it and remove all authorized keys. 

# rm /root/.ssh/authorized_keys*

Then, on the original owning Manager host, reinstall the KVM host using password authentication (for simplicity).

Note:

If the installation fails on the setup due to network issues causing the KVM host to go into a NonResponsive status on the Manager host, set the KVM host back to Maintenance mode and reinstall it with an SSH key.

Method to Remove a KVM Host That Has Become Permanently Nonfunctional

Assuming the Manager host shows the KVM host status as Nonresponsive, the following symptoms are observed:

  • The virtual machines that were running on the KVM host show a status of Unknown.

  • The following events are generated on the Manager host for this KVM host: 

    Handling non responsive Host host-name

    These events eventually fail.

Perform the following steps:

  1. Click More Actions and select Confirm Host has been Rebooted from the drop-down list.

  2. Select the Confirm Operation checkbox and click OK.

    This action causes the virtual machines to be shutdown and the host to display a value of 0 under the Virtual Machines column.

  3. Set the KVM host to Maintenance mode.
  4. Remove the KVM host.

For additional information, refer to the My Oracle Support (MOS) article How to Remove a Defunct Host From oVirt Engine (Doc ID 2540819.1).

Bug: 29685904