The encoding, database and the dog

Zabbix provides a network map feature, where images may represent triggers, hosts, host groups etc. They may show current status, problem count and lots of other data. There are some default images that may be used in the maps, and users may also upload their own. This uploading has been a problem in the past.

These images are stored in the database. The problem is, Zabbix supports 5 different databases, and they store binary data in different formats. And that resulted in users having different problems when database encoding was incorrect. Of course, maintaining data in multiple different formats is also not that easy, and updating icon set is harder than it should be.

Re-base the images

Thus the idea is to unify image storing and keep them in base64 for all databases. While that would increase the amount of space images take, it would solve lots of problems and make life easier for Zabbix users. The problem is upgrading.

Users would want to keep their existing images, probably. So upgrade should convert them to base64 (keeping support for old format would be duplicate work, and there would be no way to phase this support out later anyway. Doing this for all supported databases does not seem to be possible at this time with the upgrade process Zabbix currently uses – Zabbix database patches for going to the next major version are in SQL. Involving a separate process outside the database at this time is not considered, and storing images in the filesystem wouldn’t work because of the distributed monitoring.

So the question to the Zabbix community would be – how would you handle this problem?

And, by the way, we are looking for great PHP programmers…

11 CommentsClose Comments


  • Avatar
    Ricardo Santos
    Posted September 9, 2011 at 20:23 0Likes

    * Suggestion 1 – Create a button to “convert” old-style to new-style in frontend

    This create a new problem that zabbix doesn’t know that images are converted or not. To solve this, a “flag” should be added to “image data”. It’s very similiar to suggestion 2.

    * Suggestion 2 – Image Header

    Create a new-style “image data” with “image header”, something like “base64:AbCdE==”
    So we could support another images types like “external images” eg: “url:
    Old style could be maintained or not

    “image header” idea is based on this concept:

    • Richlv
      Posted September 10, 2011 at 09:02 0Likes

      ‘type’ flag was considered, but it leaves the problem that some users wouldn’t ever convert the images (and it goes outside the database patches – as such, there could be just a one-time external process if we go that way…)

      style is an interesting idea – would be more flexible, even if more complex. but what about current binary format, how would it be handled ?

  • Avatar
    Robert Markula
    Posted September 19, 2011 at 11:55 0Likes

    Um, sorry for the dumb question, but do images have to reside in the database at all?

    What about a dedicated image directory somewhere in the zabbix web root? All images in this folder would automatically be visible on the web frontend. No fuss with different databases, image encodings and stuff. Once implemented it would be much more intuitive to use, both for the zabbix devs and the zabbix users.

    Regarding speed regressions using an image directory, some sort of caching could be introduced.

    • Richlv
      Posted September 21, 2011 at 09:09 0Likes

      it’s definitely not a dumb question – actually, it has been considered πŸ™‚

      it would surely solve the issue with encoding, mass-adding images would be way easier and so on.

      so far the biggest argument against this – distributed mode support for images. if they would be stored at the zabbix frontend, zabbix server would have no access to them to synchronise the images.
      storing them at the zabbix server and requesting from the frontend isn’t ok either, as it would make frontend dependent on a running server.

      if the distributed mode is redesigned at some point, putting images in the frontend would be also my preferred solution, but currently it doesn’t seem to be easy enough, unfortunately

      • Avatar
        Ricardo Santos
        Posted September 26, 2011 at 21:23 0Likes

        If we allow the Zabbix frontend could create/modify files on the webserver, would become a breach of security.

        • Richlv
          Posted September 27, 2011 at 09:09 0Likes

          well, of course it would only be allowed to do that in one specific directory, and that’s an approach lots of other software uses, including mediawiki, dokuwiki, gallery… so i guess there’s a way to make that approach more or less secure. the issue seems to be with the distributed monitoring only.

  • Avatar
    Posted September 30, 2011 at 02:24 0Likes

    First let me say, I’m not a fan of Base64-ing images. I’ve recently done a project which had something like this in place and it was messy. Also, it will greatly increase the size of images in your database, and the time it takes to consume them (decoding them). If the front-ends are going to be remote from your database engine, this will increase the amount of time necessary for retrieving those images.

    Lets simplify… your problem is encoding binary image data in a database, so lets remove binary image data from the database. You mentioned that you have explored this idea, but I don’t know if you’ve explored all avenues of this. With the proposed problem above, here’s what I would do…

    First, have all built-in Zabbix images moved to part of the front-end codebase, and any user-provided images stored in a “engine” (abstract on purpose) that all front-ends can have access to. Because, the simple problem we’re solving here is image distribution, so lets distribute it!

    Some of the “engines” (see above) that can store these images are a local folder (perfect for single-front-end installs), S3, other CDNs, iSCSI/NFS (via a local file), other network-based storage engine via local-file (via FUSE), a network-based persistent key-val database engine (membase, Google BigData, Cassandra, Amazon SimpleDB) or even something simple like FTP. Then every front-end can have access to these files regardless of their location/connection/etc.

    Then the migration process would be to ask the user what method of storage you want to use, and any options necessary to use that option. Then iterate through your image table and migrate all images to that storage engine, and create a new image_paths table which just stores the reference to the image instead of binary data. Their paths would look something like…

    cassandra://mycassandraserver: 8080/image1.jpg

    I’m guessing (am I wrong?) that a _large_ number of your users are using only a single front end. I personally have about 5 single front-ends setups for my clients and employers, one is what I would consider large (+50 servers) . For these customers, this process would be especially simple and painless for them, the migration assistant can auto-suggest a folder in the existing web directory, so the user just hits “next” and they are done. And for the more enterprise-like setups with numerous front-ends and proxies they would have the technical abilities to do some of the more difficult migrations to other engines.

    Just my 2c. πŸ˜‰ My ideas above sound like fun, wish I wasn’t employed and had free time to help out! (Though I wouldn’t want to help out if you go the base64 route, lol, been there, done that, not a fan).


    • Avatar
      Posted September 30, 2011 at 02:29 0Likes

      And just thought of osmething… in a multi-front-end setup, you could also designate one of the front-ends the “image master” and only on that front-end can you upload/update images. The other front-ends get configured with the URL to your “image master” server, so they can retrieve images from it. But only your “image master” can write images to itself locally. And then if you wanted to iterate on that to improve it, write an upload-pass-thru engine to basically accept image uploads from other front-ends. Then your “image slaves” basically pass-thru image uploads directly to the “image master”, and respond to the user with what the image master would respond with. I mean, you have this fancy new API in Zabbix that I think could facilitate this front-end-to-front-end like traffic now easily! πŸ˜‰

      • Avatar
        Robert Markula
        Posted October 19, 2011 at 09:02 0Likes

        I thought about that “image master” thing as well. Well, the proposed “image engine” could also distribute new images to all frontends as soon as new images (or changes) are detected. So there is only one image repository – on a “master” frontend – and all frontends share a local cache that also works if the master frontend is down.

        Example workflow:

        1. User uploads/deletes/modifies an image on the image master
        2. The image engine periodically checks the image directory for changes
        2. As soon as a change is detected, the image engine distributes the new/changed images to all frontends (the master frontend would have to know about the other frontends)
        3. The images are present locally as identical copies on all frontends.

        The nice thing about that approach would be, that everything is done transparently to the user – all he has to do is upload an image to the master frontend, and everything else is done automatically. No worries about ssh, NFS or anything else.

        • Richlv
          Posted October 19, 2011 at 14:38 0Likes

          this sounds a bit complex on it’s own, but a big concern would be partially replicating server functionality – server already has change sync functionality in it…
          it would also require connectivity to all frontends, which currently is not needed at all.

          looks like a short term solution will be changing to decode() for pgsql image import (which was the biggest problem) and generating required sql from svgs automatically πŸ™‚

      • Richlv
        Posted October 19, 2011 at 13:55 0Likes

        this solution would make frontends depend on some remote system, which would be very, very not ok – one wouldn’t be able to view maps if the remote location goes down.

        as noted, moving images out of the db might be a good idea, but distributed mode totally prevents that…