dns_name was reset,when delete VM or detach-interface

[bailin.zhang]

When delete VM ,or detach port. the dns_name of port should be retained ,when it was assigned by the user

At this fix: https://bugs.launchpad.net/nova/mitaka/+bug/1572593. reset dns_name directly.

[Hirofumi Ichihara (ichihara-hirofumi)]

Do you expect a case like the following?

1. create a port for vm
2. boot vm with the port
3. update dns_name of the port(e.g. new_dns_name)
4. delete vm
5. now dns_name of the port is clear

Do you hope that dns_name keeps "new_dns_name" in 5?

[bailin.zhang (bailin-zhang)]

1. create a port
2. update dns-name of port
3. boot VM with this port
4. delete the Vm
5. now dns-name was reset

[Hirofumi Ichihara (ichihara-hirofumi)]

In my env(master branch), boot of 3 fails because "ortNotUsableDNS: Port 53cbccb3-49e5-4457-9890-8d2a701a458d not usable for instance 64865c07-df75-4de2-87bb-a8cdd80431dd. Value newdnsname assigned to dns_name attribute does not match instance's hostname vm1" happens.

[bailin.zhang (bailin-zhang)]

At the doc: http://docs.openstack.org/mitaka/networking-guide/adv-config-dns.html
"Instead of having the Compute service create the port for the instance, the user might have created it and assigned a value to its dns_name attribute. In this case, the value assigned to the dns_name attribute must be equal to the value that Compute service will assign to the instance’s hostname, in this example my-vm. Otherwise, the instance boot will fail"

[Hirofumi Ichihara (ichihara-hirofumi)]

What do you mean? Do you expect a case like the following?

1. create a port for vm
2. update dns-name of port(VM name which you will name to VM. This is "VM-TEST" here)
2. boot vm(the name is "VM-TEST") with the port
4. delete vm
5. now dns_name of the port is clear

However you hope dns_name of the port is "VM-TEST", right? First why did you update dns-name of the port in 2?

[bailin.zhang (bailin-zhang)]

If the dns_name of port was assigned by the user, this port can be attach to the VM named "VM-TEST" only.

When delete vm, dns_name of the port is clear. This port can be attach to any VM.

[Hirofumi Ichihara (ichihara-hirofumi)]

> When delete vm, dns_name of the port is clear. This port can be attach to any VM.
I think it's correct behavior.

[bailin.zhang (bailin-zhang)]

Before the port can be attache to the VM named "VM-TEST", but now It can be attache to any VM.
Can let a person feel confused.

I think of some solutions:
1. If the dns name is pre-existing, the dns_name of port will be retained when vm delete.
2. Prohibit users to modify dns-name manually.
3. Add a few comments, tell the uses dns-name will be clear at the process.

[Hirofumi Ichihara (ichihara-hirofumi)]

I'm not sure that there is a use case which users manually set dns-name. IMO, if there is no case, it's better to deny PUT to dns_name. And I also think that it's reasonable that we could add the comments into the documentation.

[Graham Hayes (grahamhayes)]

This seems like something that could be set in policy - services like LBaaS / Nova / Trove might want to interact with this part of the API, but maybe not users.

But, is there any reason that nova should fail to boot with a different name? I can see situations where the port might get a generated DNS name (to create both forward and reverse DNS for all ports by default), but allow it to be updated by the user to be something different.

Might be different bug report though.

[Armando Migliaccio (armando-migliaccio)]

This bug is > 180 days without activity. We are unsetting assignee and milestone and setting status to Incomplete in order to allow its expiry in 60 days.

If the bug is still valid, then update the bug status.

[Launchpad Janitor (janitor)]

[Expired for neutron because there has been no activity for 60 days.]