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posted by NCommander on Tuesday February 07 2017, @11:45AM   Printer-friendly
from the insert-systemd-rant-here dept.

So, in previous posts, I've talked about the fact that SoylentNews currently is powered on Ubuntu 14.04 + a single CentOS 6 box. Right now, the sysops have been somewhat deadlocked on what we should do going forward for our underlying operating system, and I am hoping to get community advice. Right now, the "obvious" choice of what to do is simply do-release-upgrade to Ubuntu 16.04. We've done in-place upgrades before without major issue, and I'm relatively certain we could upgrade without breaking the world. However, from my personal experience, 16.04 introduces systemd support into the stack and is not easily removable. Furthermore, at least in my personal experience, working with journalctl and such has caused me considerable headaches which I detailed in a comment awhile ago.

Discounting systemd itself, I've also found that Ubuntu 16.04 seems less "polished", for want of a better word. I've found I've had to do considerably more fiddling and tweaking to get it to work as a server distro than I had to do with previous releases, as well as had weird issues with LDAP. The same was also true when I worked with recent versions with Debian. As such, there's been a general feeling with the sysops that it's time to go somewhere else.

Below the fold are basically the options as we see them, and I hope if the community can provide some interesting insight or guidance.

Right now, we have about three years before security updates for 14.04 stop, and we are absolutely forced to migrate or upgrade. However, we're already hitting pain due to outdated software; I managed to briefly hose the DNS setup over the weekend trying to deploy CAA records for SN due to our version of BIND being outdated. When TLS 1.3 gets standardized, we're going to have a similar problem with our frontend load balancers. As such, I want to get a plan in place for migration so we can start upgrading over the next year instead of panicking and having to do something at the last moment

The SN Software Stack

As with any discussion for server operating system, knowing what our workloads and such is an important consideration. In short, this is what we use for SN, and the software we have to support

  • nginx - Loadbalancing/SSL Termination
  • Apache 2.2 + mod_perl - rehash (we run it with a separate instance of Apache and Perl, and not the system copy)
  • MySQL Cluster for production
  • MySQL standard for secondary services
  • Kerberos + Hesiod - single-signon/authetication
  • Postfix+Squirrelmail - ... mail

In addition, we use mandatory application controls (AppArmor) to limit the amount of stuff a given process can access for critical services to try and help harden security. We'd like to maintain support for this feature to whatever we migrate, either continuing with AppArmor, switching to SELinux, or using jails/zones if we switch operating systems entirely.

The Options

Right now, we've floated a few options, but we're willing to hear more.

A non-systemd Linux distro

The first choice is simply migrate over to a distribution where systemd is not present or completely optional. As of writing, Arch Linux, Gentoo, and Slackware are three such options. Our requirements for a Linux distribution is a good record of updates and security support as I don't wish to be upgrading the system once a week to a new release.

Release-based distributions

I'm aware of the Devuan project, and at first glance, it would seem like an obvious choice; Debian without systemd is the de-facto tagline. However, I've got concerns about the long-term suitability of the distribution, as well as an intentional choice to replace much of the time-tested Debian infrastructure such as the testing archive with a git-powered Jenkins instance in it's place. Another option would be slackware, but Slackware has made no indication that they won't adapt systemd, and is historically very weak with in-place upgrading and package management in general. Most of the other distributions on without-systemd.org are either LiveCDs, or are very small minority distros that I would be hesitant to bet the farm on with.

Rolling-release distributions

On the other side of the coin, and an option favored by at least some of the staff is to migrate to Gentoo or Arch, which are rolling-release. For those unaware, a rolling release distribution basically always has the latest version of everything. Security updates are handled simply by updating to the latest upstream package for the most part. I'm not a huge fan of this option, as we're dependent on self-built software, and it's not unheard of for "emerge world" to break things during upgrades due to feature changes and such. It would essentially require us to manually be checking release notes, and crossing our fingers every time we did a major upgrade. We could reduce some of this pain by simply migrating all our infrastructure to the form of ebuilds so that at least they would get rebuild as part of upgrading, but I'm very very hesitant about this option as a whole, especially for multiple machines.

Switch to FreeBSD/illumos/Other

Another way we could handle the problem is simply jump off the Linux ship entirely. From a personal perspective, I'm not exactly thrilled on the way Linux as a collective whole has gone for several years, and I see the situation only getting worse with time. As an additional benefit, switching off Linux gives us the possiblity of using real containers and ZFS, which would allow us to further isolate components of the stack, and give us the option to do rollbacks if ever necessary on a blocked upgrade; something that is difficult to impossible with most Linux distributions. As such, I've been favoring this option personally, though I'm not sold enough to make the jump. Two major options attract me of these two:

FreeBSD

FreeBSD has been around a long time, and has both considerable developer support, and support for a lot of features we'd like such as ZFS, jails, and a sane upstream. FreeBSD is split into two components, the core stack which is what constitutes a release, and the ports collection which is add-on software. Both can be upgraded (somewhat) independently of each other, so we won't have as much pain with outdated server components. We'd also have the ability to easy create jails for things like rehash, MySQL, and such and easily isolate these components from each other in a way that's more iron-clad than AppArmor or SELinux.

illumos

illumos is descended from OpenSolaris, and forked after Oracle closed up the source code for Solaris 11. Development has continued on it (at a, granted, slower place). Being the originator of ZFS, it has class A support for it, as well as zones which are functionally equivalent to FreeBSD jails. illumos also has support for SMF, which is essentially advanced service management and tracking without all the baggage systemd creates and tendrils throughout the stack. Zones can also be branded to run Linux binaries to some extent so we can handle migrating the core system over by simply installing illumos, restoring a backup into a branded zone, and then piecemeal decommissioning of said zone. As such, as an upgrade choice, this is fairly attractive. If we migrate to illumos, we'll either use the SmartOS distribution, or OpenIndiana.

Final Notes

Right now, we're basically on the fence with all options, so hopefully the community can provide their own input, or suggest other options we're not aware of. I look forward to your comments below!

~ NCommander

 
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  • (Score: 2) by DonkeyChan on Tuesday February 07 2017, @09:14PM

    by DonkeyChan (5551) on Tuesday February 07 2017, @09:14PM (#464289)

    I mean, you guys know what you're doing. The only thing I would add or adjust in your stack is to build it all into containers. Find a distro that gives you pleasant system control then don't worry about whether your stack runs on it. Focus on the OS being what you need it to be for maintenance etc and containerize the stack.

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    Total Score:   2  
  • (Score: 4, Insightful) by mechanicjay on Tuesday February 07 2017, @10:39PM

    by mechanicjay (7) <reversethis-{gro ... a} {yajcinahcem}> on Tuesday February 07 2017, @10:39PM (#464342) Homepage Journal

    I've been getting a ton of experience with Docker at my day job the last 6 months or so. I've been thinking about working on building a rehash image as a proof of concept. I've found a ton a freedom when you can completely divorce the application from the underlying OS. I agree, something like this should be on the table as well.

    --
    My VMS box beat up your Windows box.
    • (Score: 2) by DonkeyChan on Tuesday February 07 2017, @11:28PM

      by DonkeyChan (5551) on Tuesday February 07 2017, @11:28PM (#464363)

      Yeah! Whatever flavor containerization you choose to go with, being able to divorce the system from the OS like you said is an investment in future maintenance and a hedge against regression bugs.

    • (Score: 3, Informative) by NCommander on Wednesday February 08 2017, @06:51AM

      by NCommander (2) Subscriber Badge <michael@casadevall.pro> on Wednesday February 08 2017, @06:51AM (#464470) Homepage Journal

      Docker is useful for staging and separation, but not for security. If you can get root in a privilleged LXC container (which is what Docker used checked), you can break out. LXC for a long time had a rather horrid security rating because privileged containers were the only way to go.

      --
      Still always moving
      • (Score: 2) by mechanicjay on Wednesday February 08 2017, @07:32AM

        by mechanicjay (7) <reversethis-{gro ... a} {yajcinahcem}> on Wednesday February 08 2017, @07:32AM (#464476) Homepage Journal

        Yeah, there are a whole lot of security considerations with regards to root breaking out. Docker is moving pretty quick at this point and this has been a huge area of focus for the last year or so. A few sane things to do are to be sure that the process running in the container is not running as container root, then make sure you're using uid/gid mapping, which further isolates container processes in their own uid/gid range. Those combined with, of course, never running a container with the --privileged flag, and I don't think you're any worse off than running some horrid old web application on apache directly on the OS. That's at least my take on it, having wrapped about a half-dozen horrid old apps in docker in the last year. YMMV

        --
        My VMS box beat up your Windows box.
      • (Score: 0) by Anonymous Coward on Friday February 10 2017, @10:28AM

        by Anonymous Coward on Friday February 10 2017, @10:28AM (#465450)

        For what it's worth, jails on FreeBSD were designed specifically to confine root (via isolation, the original paper is titled 'confining the omnipotent root'), and with few exceptions that aren't really related to the jail implimentation itself, has not been broken out of yet, to the point that PHK has quibbed that he'd "be interested to hear from people who manage to jailbreak, as he doesn't believe it's secure". The few exceptions (with their included mitigations/fixes noted in parenthesis) include modifying the inside-jail shell that the outside-jail root attaches to (can be mitigate completely by never using jail_attach and sshing into the jail instead), using symlinks to access resources outside of jails (can be mitigated by using chroot or zfs datasets), and spoofing ip addresses (it isn't possible on default jails because socket access is not allowed, but if you need socket access VIMAGE provides the BSD full netstack).