dhcp lease rollover causes loss of access to managment IP

Bug #1274499 reported by James Page
10
This bug affects 1 person
Affects Status Importance Assigned to Milestone
MAAS
Fix Released
High
Julian Edwards
maas (Ubuntu)
New
Undecided
Unassigned

Bug Description

I've seen this a few times (and I thought we had a bug raised but it would appear not).

MAAS is attached to a /24 network with a DHCP pool limited to say 10->100 (90 IP's); the iLO/DRAC/AMT cards get a IP via DHCP OK, but then the pool is exhausted, the IP's which should of been allocated to the management cards are leased to other clients.

Its entirely possible that the management cards are not renewing leases (12 hours by default I think) resulting in this behaviour.

We worked around this by fixing the IP address allocations in /etc/maas/dhcpd.conf for the management cards, but that appears less than ideal in large deployments.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: maas 1.4+bzr1820+dfsg-0ubuntu1
ProcVersionSignature: Ubuntu 3.13.0-5.20-generic 3.13.0
Uname: Linux 3.13.0-5-generic x86_64
ApportVersion: 2.13.1-0ubuntu2
Architecture: amd64
Date: Thu Jan 30 13:08:45 2014
InstallationDate: Installed on 2014-01-23 (7 days ago)
InstallationMedia: Ubuntu-Server 13.10 "Saucy Salamander" - Release amd64 (20131016)
PackageArchitecture: all
SourcePackage: maas
UpgradeStatus: Upgraded to trusty on 2014-01-23 (7 days ago)

Related branches

Revision history for this message
James Page (james-page) wrote :
tags: added: micro-controller
Revision history for this message
Gavin Panella (allenap) wrote :

This appears to have happened in the Garage MAAS. Attached is the leases
file, which contains 141 static host maps, and references 145 different
hardware addresses. Below is a snippet from the dhcpd.conf file that was
being used at the time:

subnet 192.168.9.0 netmask 255.255.255.0 {
       filename "pxelinux.0";
       ignore-client-uids true;
       option subnet-mask 255.255.255.0;
       option broadcast-address 192.168.9.255;
       option domain-name-servers 192.168.1.25;
       option domain-name "cloud.mallards";
       option routers 192.168.9.1;
       option ntp-servers 91.189.94.4;
       range dynamic-bootp 192.168.9.10 192.168.9.150;
       class "PXE" {
          match if substring (option vendor-class-identifier, 0, 3) = "PXE";
          default-lease-time 30;
          max-lease-time 30;
       }
}

Revision history for this message
Gavin Panella (allenap) wrote :

In upstream MAAS we probably should warn users about defining overly
narrow network ranges, warn when a network is at or near capacity, and
document it all.

Changed in maas:
status: New → Triaged
importance: Undecided → High
milestone: none → 14.04
Revision history for this message
Julian Edwards (julian-edwards) wrote :

There's not much maas can do other than what Gavin says, and throw up warnings when you are nearing your range's limit.

FWIW we are going to start storing only MAC addresses for BMCs and use ARP to get their IP on the fly. It won't help with exhausted IP ranges but it will alleviate the problem of IPs changing.

Revision history for this message
Julian Edwards (julian-edwards) wrote :

If the isc-dhcp-server is allocating IPs twice then this is a bug in that package, not MAAS. Can you confirm for certain if this is the case? I thought it was just supposed to stop offering addresses if it had run out.

Changed in maas:
assignee: nobody → Julian Edwards (julian-edwards)
status: Triaged → In Progress
Changed in maas:
status: In Progress → Fix Committed
Changed in maas:
status: Fix Committed → Fix Released
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