Problem with AP predownload image (7.0.235.0 -> 7.0.240.0)

[Fredrik Hjelm]

Hi!

I´m about to upgrade 38 WLCs(WiSM w/ 4400s) from 7.0.235.0 -> 7.0.240,0 mainly because to get rid of the "W8-problem" (802.11w-capable client fails pairwise key handshake with AES.)

My apporach was to upgrade the WLCs and predownload the imgae to alla APs and then reboot at the time of the service window.

But I did a test with one WLC now and all APs wont predownload. Even after the commadn is issued and I have waited well over 600s (maximujm back-off timer), they still appear like this issuing "show ap image <AP-name>:

                                                 Predownload     Predownload

AP Name            Primary Image  Backup Image   Status          Version        Next Retry Time  Retry Count

AP001                     7.0.235.0      0.0.0.0               None            None                NA               NA

I have tried to issue the "config ap image predownload backup <AP-name> to predownload to a specific AP but no difference.

36 out of 100 APs did download the new image. I´ve read about a bug regarding predownloading i previous 7.0-versions but that problem was not simililar to my case here.

Any thoughts?

//F

.

[Scott Fella]

Well what model AP's. older models that don't have enough memory will not download the other image. Also AP's that have a lot of crash files and or other files that take up a lot of memory have no room to download the other image.

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[Fredrik Hjelm]

Some more info:

The APs are AP1142.

And this is the output after issuing "config ap image predownload backup all"

Thers is no failed downloads which seems strange to me, given the result of the command.

>show ap image all

Total number of APs.............................. 102

Number of APs

        Initiated....................................... 0

        Predownloading.................................. 0

        Completed predownloading........................ 36

        Not Supported................................... 0

        Failed to Predownload........................... 0

[Scott Fella]

FYI...

Note These access point models do not support predownloading of images: 1120, 1230, and 1310.

Guidelines and Limitations for Predownloading Images
Follow these guidelines when you use image predownloading:
•The maximum number of concurrent predownloads is limited to half the number of concurrent normal image downloads. This limitation allows new access points to join the controller during image downloading.
If you reach the predownload limit, then the access points that cannot get an image sleep for a time between 180 to 600 seconds and then reattempt the predownload.
•Before you enter the predownload command, you should change the active controller boot image to the backup image. This step ensures that if the controller reboots for some reason, it comes back up with the earlier running image, not the partially downloaded upgrade image.
•Access points with 16-MB total available memory (1130 and 1240 access points) may not have enough free memory to download an upgrade image and may automatically delete crash info files, radio files, and any backup images to free up space. However, this limitation does not affect the predownload process because the predownload image replaces any backup image on the access point.
•When the system time is changed by using the config time command, the time set for scheduled reset will not be valid and the scheduled system reset will be canceled. You are given an option either to cancel the scheduled reset before configuring the time or retain the scheduled reset and not configure the time.
•All the primary, secondary, and tertiary controllers should run the same images as the primary and backup images. That is, the primary image of all three controllers should be X and the secondary image of all three controllers should be Y or the feature will not be effective.
•At the time of the reset, if any AP is downloading the controller image, the scheduled reset is canceled. The following message appears with the reason why the scheduled reset was canceled:
%OSAPI-3-RESETSYSTEM_FAILED: osapi_task.c:4458 System will not reset as software is
being upgraded.

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[Fredrik Hjelm]

Yes I´ve read those but I cant see that I´m missing something....

The AP1140 has 32 MB memory so that should not be an issue? Or if it is, the AP "may automatically delete crash info files, radio files, and any backup images to free up space. However, this limitation does not affect the predownload process because the predownload image replaces any backup image on the access point.

Right now,  I´m not seeing the upside with predownloading... :-)

[Scott Fella]

The AP needs room for the other image. Don't think of it as a backup image, because you can store many images on an AP. SSH/Telnet or console into the ap that is a problem and issue a show dir. If you have enough memory, it should work. If you have extra files you don't need, then you need to delete them.

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[Scott Fella]

I understand your frustration, but I don't make these limitations. I have not had too many issue when doing these, but recently had to upgrade a few hundred old AP's that couldn't use the pre image download. Also a few that were able to use the pre image download had crash files that took up all the memory.

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[Fredrik Hjelm]

Thank for your help and encouragement! =)

But I have about 5000 AP1142 that is associated to a WiSM and then is effected by the upgrade. It doesnt seem feasible to check 60 % of them individually if its the same on the other 37 WLCs. =)

But I will still try to get this to work!

[Scott Fella]

Come to think of it, are you pushing it out to all the AP's at once? I think the WiSM only can push if to 10 at a time.

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[Scott Fella]

Use the CLI to test.

Specifying Access Points for Predownload
Use one of these commands to specify access points for predownload:
•Specify access points for predownload by entering this command:
config ap image predownload {primary | backup} {ap_name | all}
The primary image is the new image; the backup image is the existing image. Access points always boot with the primary image.

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[Fredrik Hjelm]

Yes I did issue the "config ap image predownload backup all". I thought the WLCs did manage the que with the back-off timers.

I now found one reason for some of the APs after SSH into inte of them. I forgot that we have some AP1131, which dont have enough memory.

I did the same on a AP1142 and it has 32126976 bytes total (24678912 bytes free), which should be a problem.

[Scott Fella]

The 1142 should be fine. Try to just pre download that AP by itself to see.

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[Fredrik Hjelm]

Yes I did and nothing happens.....

[Scott Fella]

Interesting. Yeah I don't know unless the WiSM is queuing these up. Do you see any more that have successfully downloaded the image? Typically if you upgrade the WiSM and you reboot it, the WiSM will only upgrade 10 max.

Here is a link to George's blog who also post on this forum

http://www.my80211.com/cisco-wlc-cli-commands/2011/2/20/wlc-predownload-the-image-to-the-access-points-from-the-cont.html

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[Fredrik Hjelm]

I´ve read Geogres blog post already, good info there!

I can see 36 APs which successfully predownloaded the new image. 

I feel that there is too many APs to do a investigation on every one that dont have a success predownload,,,,