qemu:Use QMP to set bootindex dynamically

[Prashanth684]

With this change the bootindex is changed dynamically rather than being statically fed in during VM creation.
One of the problematic areas was s390x where the network device needs to have bootindex 1 but on subsequent boots
it needs to boot from disk. This helps in that situation of not setting a bootindex for the primary disk initially
but setting it later to avoid the bootindex conflict.

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[Prashanth684]

Taking a stab at @cgwalters suggestion from #1336

[Prashanth684]

@cgwalters or somebody - could you help me with updating the vendor for github.com/digitalocean/go-qemu/ ? I did try with an older version of the assembler and tested with that and it works fine. But on the latest assembler, when i try a go mod tidy and go mod vendor i get build errors. I am also not super comfortable with go modules in general and I am afraid I will mess something up.

[arithx]

@cgwalters or somebody - could you help me with updating the vendor for github.com/digitalocean/go-qemu/ ? I did try with an older version of the assembler and tested with that and it works fine. But on the latest assembler, when i try a go mod tidy and go mod vendor i get build errors. I am also not super comfortable with go modules in general and I am afraid I will mess something up.

What error were you specifically seeing?

[cgwalters]

I'm not seeing any changes to metal.go - I'd expect to see that because basically we need to do:

• PXE boot
• [guest] systemd unit like rebootUnit in metal.go except writes to a virtio-serial channel (hm, needs to block and wait for response, so we need bidirectional channels)
• [host] read from virtio-serial channel and uses QMP to adjust bootorder
• [guest] continue reboot

right?

[Prashanth684]

@cgwalters or somebody - could you help me with updating the vendor for github.com/digitalocean/go-qemu/ ? I did try with an older version of the assembler and tested with that and it works fine. But on the latest assembler, when i try a go mod tidy and go mod vendor i get build errors. I am also not super comfortable with go modules in general and I am afraid I will mess something up.

What error were you specifically seeing?

When I do a go mod tidy and a go mod vendor in the mantle directory and try a build - i see this:

09:16:19 psundara@psundara mantle$./build
Building kola
# github.com/coreos/mantle/platform/api/openstack
platform/api/openstack/api.go:363:13: undefined: groups.IDFromName
09:16:36 psundara@psundara mantle$

[Prashanth684]

I'm not seeing any changes to metal.go - I'd expect to see that because basically we need to do:

• PXE boot
• [guest] systemd unit like rebootUnit in metal.go except writes to a virtio-serial channel (hm, needs to block and wait for response, so we need bidirectional channels)
• [host] read from virtio-serial channel and uses QMP to adjust bootorder
• [guest] continue reboot

right?

Hmm..Ok sorry I think I misunderstood your initial comment then - i did this change just from the perspective of setting the bootindex dynamically so the s390x testiso would work. Would it be possible that we can make the change incrementally and I will let you/someone else pick up the rest of the changes?

[cgwalters]

Would it be possible that we can make the change incrementally

Yep #1336 (comment)

[Prashanth684]

Would it be possible that we can make the change incrementally

Yep #1336 (comment)

Opened #1350. Couldn't reopen the old one as i had already rebased it. sorry for the back and forth.

[arithx]

@cgwalters or somebody - could you help me with updating the vendor for github.com/digitalocean/go-qemu/ ? I did try with an older version of the assembler and tested with that and it works fine. But on the latest assembler, when i try a go mod tidy and go mod vendor i get build errors. I am also not super comfortable with go modules in general and I am afraid I will mess something up.

What error were you specifically seeing?

When I do a go mod tidy and a go mod vendor in the mantle directory and try a build - i see this:

09:16:19 psundara@psundara mantle$./build
Building kola
# github.com/coreos/mantle/platform/api/openstack
platform/api/openstack/api.go:363:13: undefined: groups.IDFromName
09:16:36 psundara@psundara mantle$

The groups.IDFromName function that isn't being found is a call being made to the openstack API. It seems like they've dropped it in whichever version you're trying to bump to. You'd probably just need to find the equivalent function or re-work the existing getSecurityGroup function to use a different function resulting in the same functionality.

[Prashanth684]

@cgwalters or somebody - could you help me with updating the vendor for github.com/digitalocean/go-qemu/ ? I did try with an older version of the assembler and tested with that and it works fine. But on the latest assembler, when i try a go mod tidy and go mod vendor i get build errors. I am also not super comfortable with go modules in general and I am afraid I will mess something up.

What error were you specifically seeing?

When I do a go mod tidy and a go mod vendor in the mantle directory and try a build - i see this:

09:16:19 psundara@psundara mantle$./build
Building kola
# github.com/coreos/mantle/platform/api/openstack
platform/api/openstack/api.go:363:13: undefined: groups.IDFromName
09:16:36 psundara@psundara mantle$

The groups.IDFromName function that isn't being found is a call being made to the openstack API. It seems like they've dropped it in whichever version you're trying to bump to. You'd probably just need to find the equivalent function or re-work the existing getSecurityGroup function to use a different function resulting in the same functionality.

Ok..i can do that..but is there a way through go mod to just add a single dependent package? not sure there is.

[arithx]

Ok..i can do that..but is there a way through go mod to just add a single dependent package? not sure there is.

If you mean bumping the version only for a specific package of the larger library (thus leaving the other packages at a different version) then to my knowledge there isn't a way. If you mean adding only a specific package from a library then there should be, iirc it only adds the packages being used from a library.

[jlebon]

Using QMP to change the bootindex is nice!

I think this also allows us to stop special-casing s390x as done in #1350, right? (See also #1350 (comment)).

[Prashanth684]

Ok..i can do that..but is there a way through go mod to just add a single dependent package? not sure there is.

If you mean bumping the version only for a specific package of the larger library (thus leaving the other packages at a different version) then to my knowledge there isn't a way. If you mean adding only a specific package from a library then there should be, iirc it only adds the packages being used from a library.

Using QMP to change the bootindex is nice!

I think this also allows us to stop special-casing s390x as done in #1350, right? (See also #1350 (comment)).

Correct. But this is just a part of the bigger changes that @cgwalters is suggesting above

[Prashanth684]

Ok..i can do that..but is there a way through go mod to just add a single dependent package? not sure there is.

If you mean bumping the version only for a specific package of the larger library (thus leaving the other packages at a different version) then to my knowledge there isn't a way. If you mean adding only a specific package from a library then there should be, iirc it only adds the packages being used from a library.

Thanks! was able to pull just that module in and got it to work.

[cgwalters]

[guest] systemd unit like rebootUnit in metal.go except writes to a virtio-serial channel (hm, needs to block and wait for response, so we need bidirectional channels)

Or, more closely matching Foreman/Ironic etc. - run a webserver on the host and have it accept a POST which switches the bootorder.

[Prashanth684]

I'm not seeing any changes to metal.go - I'd expect to see that because basically we need to do:

• PXE boot
• [guest] systemd unit like rebootUnit in metal.go except writes to a virtio-serial channel (hm, needs to block and wait for response, so we need bidirectional channels)
• [host] read from virtio-serial channel and uses QMP to adjust bootorder
• [guest] continue reboot

right?

@cgwalters i'm afraid i need some clarity on this. I think my understanding is not sufficient. I thought setting the bootindex in the builder.Exec would take care of all cases including metal and it would also be valid on reboots. What is it that we are trying to achieve here?

[cgwalters]

No worries; I can take this at some point hopefully soon. Thanks for starting this!

What is it that we are trying to achieve here?

To dynamically switch the boot order after an install is complete, before the reboot.

[openshift-ci-robot]

@Prashanth684: PR needs rebase.

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