On Wed, Nov 4, 2020 at 9:49 PM Nir Soffer <nsoffer(a)redhat.com> wrote:
I want to share useful info from the OST hackathon we had this week.
Image transfer must work with real hostnames to allow server
certificate verification.
Inside the OST environment, engine and hosts names are resolvable, but
on the host
(or vm) running OST, the names are not available.
This can be fixed by adding the engine and hosts to /etc/hosts like this:
$ cat /etc/hosts
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
192.168.200.2 engine
192.168.200.3 lago-basic-suite-master-host-0
192.168.200.4 lago-basic-suite-master-host-1
Are these addresses guaranteed to be static?
Where are they defined?
It would be if this was automated by OST. You can get the details using:
$ cd src/ovirt-system-tests/deployment-xxx
$ lago status
It would have been even nicer if it was possible/easy to have this working
dynamically without user intervention.
Thought about and searched for ways to achieve this, failed to find something
simple.
Closest options I found, in case someone feels like playing with this:
1. Use HOSTALIASES. 'man 7 hostname' for details, or e.g.:
https://blog.tremily.us/posts/HOSTALIASES/
With this, if indeed the addresses are static, but you do not want to have
them hardcoded in /etc (say, because you want different ones per different
runs/needs/whatever), you can add them hardcoded there with some longer
name, and have a process-specific HOSTALIASES file mapping e.g. 'engine'
to the engine of this specific run.
2.
https://github.com/fritzw/ld-preload-open
With this, you can have a process-specific /etc/resolv.conf, pointing
this specific process to the internal nameserver inside lago/OST.
This requires building this small C library. Didn't try it or check
its code. Also can't find it pre-built in copr (or anywhere).
(
Along the way, if you like such tricks, found this:
https://github.com/gaul/awesome-ld-preload
)
OST keeps the deployment directory in the source directory. Be careful if you
like to "git clean -dxf' since it will delete all the deployment and
you will have to
kill the vms manually later.
The next thing we need is the engine ca cert. It can be fetched like this:
$ curl -k
'https://engine/ovirt-engine/services/pki-resource?resource=ca-certificate&format=X509-PEM-CA'
> ca.pem
I would expect OST to do this and put the file in the deployment directory.
To upload or download images, backup vms or use other modern examples from
the sdk, you need to have a configuration file like this:
$ cat ~/.config/ovirt.conf
[engine]
engine_url =
https://engine
username = admin@internal
password = 123
cafile = ca.pem
With this uploading from the same directory where ca.pem is located
will work. If you want
it to work from any directory, use absolute path to the file.
I created a test image using qemu-img and qemu-io:
$ qemu-img create -f qcow2 test.qcow2 1g
To write some data to the test image we can use qemu-io. This writes 64k of data
(b"\xf0" * 64 * 1024) to offset 1 MiB.
$ qemu-io -f qcow2 -c "write -P 240 1m 64k" test.qcow2
Never heard about qemu-io. Nice to know. Seems like it does not have a manpage,
in el8, although I can find such a manpage elsewhere on the net.
Since this image contains only 64k of data, uploading it should be instant.
The last part we need is the imageio client package:
$ dnf install ovirt-imageio-client
To upload the image, we need at least one host up and storage domains
created. I did not find a way to prepare OST, so simply run this after
run_tests completed. It took about an hour.
To upload the image to raw sparse disk we can use:
$ python3 /usr/share/doc/python3-ovirt-engine-sdk4/examples/upload_disk.py
-c engine --sd-name nfs --disk-sparse --disk-format raw test.qcow2
[ 0.0 ] Checking image...
[ 0.0 ] Image format: qcow2
[ 0.0 ] Disk format: raw
[ 0.0 ] Disk content type: data
[ 0.0 ] Disk provisioned size: 1073741824
[ 0.0 ] Disk initial size: 1073741824
[ 0.0 ] Disk name: test.raw
[ 0.0 ] Disk backup: False
[ 0.0 ] Connecting...
[ 0.0 ] Creating disk...
[ 36.3 ] Disk ID: 26df08cf-3dec-47b9-b776-0e2bc564b6d5
[ 36.3 ] Creating image transfer...
[ 38.2 ] Transfer ID: de8cfac9-ead2-4304-b18b-a1779d647716
[ 38.2 ] Transfer host name: lago-basic-suite-master-host-1
[ 38.2 ] Uploading image...
[ 100.00% ] 1.00 GiB, 1.79 seconds, 571.50 MiB/s
[ 40.0 ] Finalizing image transfer...
[ 44.1 ] Upload completed successfully
I uploaded this before I added the hosts to /etc/hosts, so the upload
was done via the proxy.
Yes, it took 36 seconds to create the disk.
To download the disk use:
$ python3 /usr/share/doc/python3-ovirt-engine-sdk4/examples/download_disk.py
-c engine 5ac63c72-6296-46b1-a068-b1039c8ecbd1 downlaod.qcow2
[ 0.0 ] Connecting...
[ 0.2 ] Creating image transfer...
[ 1.6 ] Transfer ID: a99e2a43-8360-4661-81dc-02828a88d586
[ 1.6 ] Transfer host name: lago-basic-suite-master-host-1
[ 1.6 ] Downloading image...
[ 100.00% ] 1.00 GiB, 0.32 seconds, 3.10 GiB/s
[ 1.9 ] Finalizing image transfer...
We can verify the transfers using checksums. Here we create a checksum
of the remote
disk:
$ python3 /usr/share/doc/python3-ovirt-engine-sdk4/examples/checksum_disk.py
-c engine 26df08cf-3dec-47b9-b776-0e2bc564b6d5
{
"algorithm": "blake2b",
"block_size": 4194304,
"checksum":
"a79a1efae73484e0218403e6eb715cdf109c8e99c2200265b779369339cf347b"
}
And checksum of the downloaded image - they should match:
$ python3 /usr/share/doc/python3-ovirt-engine-sdk4/examples/checksum_image.py
downlaod.qcow2
{
"algorithm": "blake2b",
"block_size": 4194304,
"checksum":
"a79a1efae73484e0218403e6eb715cdf109c8e99c2200265b779369339cf347b"
}
Same upload to iscsi domain, using qcow2 format:
$ python3 /usr/share/doc/python3-ovirt-engine-sdk4/examples/upload_disk.py
-c engine --sd-name iscsi --disk-sparse --disk-format qcow2 test.qcow2
[ 0.0 ] Checking image...
[ 0.0 ] Image format: qcow2
[ 0.0 ] Disk format: cow
[ 0.0 ] Disk content type: data
[ 0.0 ] Disk provisioned size: 1073741824
[ 0.0 ] Disk initial size: 458752
[ 0.0 ] Disk name: test.qcow2
[ 0.0 ] Disk backup: False
[ 0.0 ] Connecting...
[ 0.0 ] Creating disk...
[ 27.8 ] Disk ID: e7ef253e-7baa-4d4a-a9b2-1a6b7db13f41
[ 27.8 ] Creating image transfer...
[ 30.0 ] Transfer ID: 88328857-ac99-4ee1-9618-6b3cd14a7db8
[ 30.0 ] Transfer host name: lago-basic-suite-master-host-0
[ 30.0 ] Uploading image...
[ 100.00% ] 1.00 GiB, 0.31 seconds, 3.28 GiB/s
[ 30.3 ] Finalizing image transfer...
[ 35.4 ] Upload completed successfully
Again, creating the disk is very slow, not sure why. Probably having a storage
server on a nested vm is not a good idea.
We can compare the checksum with the source image since checksum are computed
from the guest content:
[nsoffer@ost ~]$ python3
/usr/share/doc/python3-ovirt-engine-sdk4/examples/checksum_disk.py -c
engine e7ef253e-7baa-4d4a-a9b2-1a6b7db13f41
{
"algorithm": "blake2b",
"block_size": 4194304,
"checksum":
"a79a1efae73484e0218403e6eb715cdf109c8e99c2200265b779369339cf347b"
}
Finally, we can try real images using virt-builder:
$ virt-builder fedora-32
Will create a new Fedora 32 server image in the current directory. See
--help for many
useful options to create different format, set root password, or
install packages.
Uploading this image is much slower:
$ python3 /usr/share/doc/python3-ovirt-engine-sdk4/examples/upload_disk.py
-c engine --sd-name nfs --disk-sparse --disk-format raw fedora-32.img
[ 0.0 ] Checking image...
[ 0.0 ] Image format: raw
[ 0.0 ] Disk format: raw
[ 0.0 ] Disk content type: data
[ 0.0 ] Disk provisioned size: 6442450944
[ 0.0 ] Disk initial size: 6442450944
[ 0.0 ] Disk name: fedora-32.raw
[ 0.0 ] Disk backup: False
[ 0.0 ] Connecting...
[ 0.0 ] Creating disk...
[ 36.8 ] Disk ID: b17126f3-fa03-4c22-8f59-ef599b64a42e
[ 36.8 ] Creating image transfer...
[ 38.5 ] Transfer ID: fe82fb86-b87a-4e49-b9cd-f1f4334e7852
[ 38.5 ] Transfer host name: lago-basic-suite-master-host-0
[ 38.5 ] Uploading image...
[ 100.00% ] 6.00 GiB, 99.71 seconds, 61.62 MiB/s
[ 138.2 ] Finalizing image transfer...
[ 147.8 ] Upload completed successfully
At the current state of OST, we should avoid such long tests.
Did you try to check if it's indeed actually plain IO that's
slowing disk creation? Perhaps it's something else?
Using backup_vm.py and other examples should work in the same way.
I posted this patch to improve nfs performance, please review:
https://gerrit.ovirt.org/c/112067/
Nice.
Thanks and best regards,
--
Didi