On Tue, Nov 27, 2018 at 4:01 PM Ranjit DSouza <Ranjit.DSouza@veritas.com> wrote:

Does Image Transfer work without Authorization header?


Yes you don't need this any more.

This header was required in old versions of the proxy. If you target 4.2, you don't
need it.

The authentication system works like this:
- you authenticate with engine
- you start a transfer for upload or download
- engine setup a transfer ticket on one of the hosts, including a random uuid
- engine returns a url including this random uuid (proxy_url, transfer_url)
- you use the url to upload or download the data
- when you are done, engine remove the transfer ticket from the host

The authorization header is used now only internally to install a transfer ticket
in the proxy.

Nir

 

This is one which holds the signed ticket during download/Upload operation. Turns out, due to an issue in our code (which I mentioned below), this was not getting sent all along, yet, the download was successful. No http error codes can be seen.

Not sure whether we have turned this off (unknowingly)  on the RHV server, or there is a setting for that.

 

Thanks for your reply.

Regards,

Ranjit

 

From: Nir Soffer [mailto:nsoffer@redhat.com]
Sent: Monday, November 26, 2018 7:36 PM
To: Ranjit DSouza <Ranjit.DSouza@veritas.com>
Cc: devel <devel@ovirt.org>; Pavan Chavva <pchavva@redhat.com>; Suchitra Herwadkar <Suchitra.Herwadkar@veritas.com>; Abhay Marode <Abhay.Marode@veritas.com>; Mahesh Falmari <Mahesh.Falmari@veritas.com>; Raj Asher <Raj.Asher@veritas.com>
Subject: Re: [EXTERNAL] Re: mismatch in disk size while uploading a disk in chunks using Image Transfer

 

On Mon, Nov 26, 2018 at 4:00 PM Ranjit DSouza <Ranjit.DSouza@veritas.com> wrote:

Nir

 

I think you were spot on with the content-range not getting sent to RHV server. Good catch!

 

Ok so that problem was in our http client code where we were not setting this header in libcurl. Now that we have moved forward, we are seeing that the restored disk actual_size is 4k over the provisioned size.

 

actual size is the allocated size on storage - basically:

 

    st_blocks * 512

 

We know that sometimes creating fully allocated disk show st_size + 4k. I don't know

why this happens but it does not change anything for the guest or for oVirt.

 

The important check is having exactly st_size bytes in the upload - same as in the

uploaded file, and checking that both contain the same content.

 

Nir

 

 

{

  "actual_size" : "3221229568", //this is 3GB + 4k

  "alias" : "vmRestoreDisk",

  "content_type" : "data",

  "format" : "raw",

  "image_id" : "b69363da-620e-4f55-a3c7-1481e85c4164",

  "propagate_errors" : "false",

  "provisioned_size" : "3221225472",

  "shareable" : "false",

  "sparse" : "true",

  "status" : "ok",

  "storage_type" : "image",

  "total_size" : "0",

  "wipe_after_delete" : "false",

  "disk_profile" : {

    "href" : "/ovirt-engine/api/diskprofiles/555ef5b2-807e-4f21-9a32-0494686515e4",

    "id" : "555ef5b2-807e-4f21-9a32-0494686515e4"

  },

 

I was expecting it to be 1 GB as was the original disk. But I am able to boot the vm and log in and look at the directories, (earlier I was getting an error when I opened the console that it was not a bootable disk)

 

{

  "actual_size" : "1389109248",

  "alias" : "3gbdisk",

  "content_type" : "data",

  "format" : "raw",

  "image_id" : "8fbac55e-0c86-4c0b-911b-f5b0a6722834",

  "propagate_errors" : "false",

  "provisioned_size" : "3221225472",

  "shareable" : "false",

  "sparse" : "true",

  "status" : "ok",

 

 

I am going through the var/log/ovirt-imageio-daemon logs to check for any clues. In the meanwhile, do let us know your thoughts on why this may have happened.

(we are taking your performance related comments seriously and will work on it once we are done with this)

 

Thanks

Ranjit

 

From: Nir Soffer [mailto:nsoffer@redhat.com]
Sent: Saturday, November 24, 2018 12:17 AM
To: Ranjit DSouza <Ranjit.DSouza@veritas.com>
Cc: devel <devel@ovirt.org>; Pavan Chavva <pchavva@redhat.com>; Suchitra Herwadkar <Suchitra.Herwadkar@veritas.com>; Abhay Marode <Abhay.Marode@veritas.com>
Subject: [EXTERNAL] Re: mismatch in disk size while uploading a disk in chunks using Image Transfer

 

On Fri, Nov 23, 2018 at 2:49 PM Ranjit DSouza <Ranjit.DSouza@veritas.com> wrote:

... 

I am trying to upload a snapshot disk in chunks. Everything seems to work fine, but observed that the actual_size after upload, is much lesser than the actual_size of the original disk.

 

Here are the steps:

1.       Take a snapshot of a vm disk and download it (using Image Transfer mechanism). Save it on the file system somewhere.  This disk name is 3gbdisk. It is Raw + sparse. Resides on nfs storage. The size of this downloaded file is 3 GB.

 

  "actual_size" : "1389109248", //1 GB

 

This is the allocated size (what du -sh filename will show).

 

But in 4.2 we do not support yet detection of zero or unallocated areas in the image,

so you always download the complete image. Zero or unallocated areas are downloaded

as zeros.

 

...

 2.       Now create a new floating disk, (raw + sparse), with provisioned_size = 3221225472, or 3 GB. This disk name is vmRestoreDisk

3.       Upload to this disk using Image Transfer API, using libCurl  in chunks of 128 MB. This is done in a while loop,  sequentially reading portions of the file downloaded in step 1 and uploading these chunks via libcurl.  I Use the Transfer URL, not proxy URL.

 

Here is the trace of the first chunk. Note the Content-Range and Content-Length headers. Start offset = 0, end offset = 134217727 (or 128 MB)

 

upload request for chunk, start offset: 0, end offset: 134217727

Upload Started

Header:Content-Range: bytes 0-134217727/3221225472

 

The Content-Range header looks correct...

 

Header:Content-Length: 3221225472

*   Trying 10.210.46.215...

* TCP_NODELAY set

* Connected to pnm86hpch30bl15.pne.ven.veritas.com (10.210.46.215) port 54322 (#0)

* ALPN, offering http/1.1

* Cipher selection: ALL:!EXPORT:!EXPORT40:!EXPORT56:!aNULL:!LOW:!RC4:@STRENGTH

* SSL connection using TLSv1.2 / ECDHE-RSA-AES256-GCM-SHA384

* ALPN, server did not agree to a protocol

* Server certificate:

*  subject: O=pne.ven.veritas.com; CN=pnm86hpch30bl15.pne.ven.veritas.com

*  start date: Oct  7 08:55:24 2018 GMT

*  expire date: Oct  7 08:55:24 2023 GMT

*  issuer: C=US; O=pne.ven.veritas.com; CN=pravauto20.pne.ven.veritas.com.59289

*  SSL certificate verify result: unable to get local issuer certificate (20), continuing anyway.

> PUT /images/8ebc9fa8-d322-423e-8a14-5e46ca10ed4e HTTP/1.1

Host: pnm86hpch30bl15.pne.ven.veritas.com:54322

Accept: */*

Content-Length: 134217728

Expect: 100-continue

 

But you did not send the Content-Range header for this request...

 

 

* Done waiting for 100-continue

* We are completely uploaded and fine

* HTTP 1.0, assume close after body

< HTTP/1.0 200 OK

 

The request was successful, writing the first 128 MiB...

 

< Date: Fri, 23 Nov 2018 11:52:53 GMT

< Server: WSGIServer/0.1 Python/2.7.5

< Content-Type: application/json; charset=UTF-8

< Content-Length: 0

< 

* Closing connection 0

http response code from curl 200

Upload Finished. Return Value: 0

 

Looking in the attached trace, you never sent the Content-Range, so imageio

happily wrote all chunks to the start of the image...

 

4.       Finalize the Image Transfer after all chunks are uploaded. Observed that the disk status goes from ‘uploading via API’ to finalizing to OK.

5.       Do a GET call on the disk (vmRestoreDisk).

  "actual_size" : "134217728", //128MB

 

Which explain why the file size is smaller than expected.

 

  "alias" : "vmRestoreDisk",

  "content_type" : "data",

  "format" : "raw",

  "image_id" : "3eda3df2-514a-4e78-b999-1729216b25db",

  "propagate_errors" : "false",

  "provisioned_size" : "3221225472",

  "shareable" : "false",

  "sparse" : "true",

  "status" : "ok",

  "storage_type" : "image",

  "total_size" : "0",

  "wipe_after_delete" : "false",

 

As you can see, the actual size is just 128 MB, not 1 GB.  I have attached the logs of the upload operation. I think I may be missing something, let me know in case you need further information.

 

Please always include the relevant part from

/var/log/ovirt-imageio-daemon/daemon.log

 

If you check this log you will find that all requests for this upload have:

 

WRITE offset=0 size=134217728 ...

 

Other issue I see in the attached trace:

 

- You close the connection after every request - this is not needed and reduce throughput

  use the same connection for the entire request

 

- libcurl sends "Expect: 100-continue" header, but imageio does not handle this yet in 

  4.2. This may cause 1 second delay for every request, when libcurl wait for

  "100 Continue" response, before sending the payload. This feature should be available

  in 4.3[4]. Until this feature is supported it would be good idea to disable 100-continue

  header in libcurl[5]. If you cannot disable the option, you can change the timeout[6] to

  avoid the delay.

 

- You don't check the server capabilities using OPTIONS[0] request. Every upload sholud

  start by checking the server capabilities so you can optimize the upload using zero and

  flush operations.

 

- You don't use the ?flush=no query string - this is recommended for improving performance

  if you use flush=no, you should send PATCH/flush[1] request at the end of the transfer.

 

- It would be more efficient to send bigger chunks. The size of the chunk is depends on

  the amount of data you like to resend if a request fails.

 

- You can speed up the upload if you detect zero areas in the image and send them

  using PATCH/zero[2] request.

 

For example using all these features, see imageio python client[3]. If you can use the

client you will get all this for free. Otherwise you can use it as example code for 

implementing the upload in another language.

 

 

Nir