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  • 1.  MX104 upgrade path 17.3R3.10 to 20.4

    Posted 11-16-2022 14:32

    I am trying to figure out the best and most efficient upgrade path to upgrade our two mx104 routers from 17.3R3.10 to 20.4.

    You can upgrade or downgrade to the EEOL release that occurs directly before or after the currently installed EEOL release, or to two EEOL releases before or after. For example, Junos OS Releases 19.2, 19.3, and 19.4 are EEOL releases. You can upgrade from Junos OS Release 19.2 to Release 19.3 or from Junos OS Release 19.2 to Release 19.4. You cannot upgrade directly from a non-EEOL release to a release that is more than three releases ahead or behind. To upgrade or downgrade from a non-EEOL release to a release more than three releases before or after, first upgrade to the next EEOL release and then upgrade or downgrade from that EEOL release to your target release. For more information about EEOL releases and to review a list of EEOL releases, see https://www.juniper.net/support/eol/junos.html.

    If I understand the above explanation correctly this would mean:
    17.3R3.10 -> Junos OS 18.1 -> Junos OS 18.3 -> Junos OS 19.1 -> Junos OS 19.3 -> Junos OS 20.1 -> Junos OS 20.3 -> Junos OS 20.4

    Can anyone confirm this? Isn't there a faster path possible from one major release to another?

    Thanks in advance for the feedback.

    Kind regards


  • 2.  RE: MX104 upgrade path 17.3R3.10 to 20.4

    Posted 11-17-2022 04:13
    Hi Yannick,

    From my understanding it doesn't matter all that much anymore these days and you can safely upgrade in bigger leaps. The recommend process is to upgrade to the final main release of a version (typically the .4R3 release) and from there upgrade to 20.4R3 (I would recommend going to 20.4R3-S5, which is the latest service release and fixes a few fairly significant bugs, but it depends on your network whether these would be of relevance to you of course).

    Recommendation by Juniper is to not skip more than 2 releases (so 17 to 20 skips 18 and 19 so that would work) as long as you are on the final release of the train you are upgrading from. The main reason for this is that the FreeBSD version gets upgraded occasionally among other things, so if you take too big leaps you might run into compatibility issues. That's not to say that it's not possible, it's mainly a recommendation though especially when dealing with production devices it's probably best to follow that.

  • 3.  RE: MX104 upgrade path 17.3R3.10 to 20.4

    Posted 11-17-2022 11:53
    In your quote of the 20.4 upgrade/Downgrade support policy (for what it's worth...) you missed out the first line...

    Support for upgrades and downgrades that span more than three Junos OS releases at a time is not provided, except for releases that are designated as Extended End-of-Life (EEOL) releases. EEOL releases provide direct upgrade and downgrade paths-you can upgrade directly from one EEOL release to the next EEOL release even though EEOL releases generally occur in increments beyond three releases

    The the "supported" (*cough*) upgrade path can be described as "skip 2" (always) or "skip 1 EEOL" (if start and end are EEOL).
    Since all releases between 13.3 and 19.4 were designated "EEOL", the EEOL rule has been pretty much pointless for a while.
    Since 20.1 it's back though, with only the .2 and .4 releases being EEOL.

    > 17.3R3.10 -> Junos OS 18.1 -> Junos OS 18.3 -> Junos OS 19.1 -> Junos OS 19.3 -> Junos OS 20.1 ->
    Junos OS 20.3 -> Junos OS 20.4

    You've done "they are EEOL, so can only skip 1", but the "you can always skip 2" is still true, so it would actually be;
    17.3R3.10 -(skip 2)> 18.2 -(skip 2)> 19.1 -(skip 2)> 19.4 -(skip 1 EEOL (20.2))> 20.4

    Yes, they really messed this up.
    I assume everyone ignores this "supported" upgrade path, and falls back on "try it in lab, test it, if it's ok, do it in prod", don't tell JTAC when you open a ticket.
    or does a lot of enforced upgrades due to issues, so are always doing "supported" upgrades.
    or does RE swaps with an upgrades RE.
    or boots from USB and installs fresh.
    Anything to avoid that nonsense above.

    Not that you asked, but I'll note that the LSV for the MX104 is already out, and already had all of the "planned" Maintenance and Service release (it's at 21.2R3-S3), so it's on "SIRT only" fixes now. If it doesn't work now, it's not going to get any better.
    I've not actually tested it to see if it is actually any better/worse than 20.4, but it's SIRT fix window is 6 months longer than 20.4 if that's an important metric for you.