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Message #00464
[Bug 1103260] Re: fixed_ips cannot reliably be released on instance termination
** Changed in: nova
Status: Fix Committed => Fix Released
** Changed in: nova
Milestone: None => grizzly-3
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https://bugs.launchpad.net/bugs/1103260
Title:
fixed_ips cannot reliably be released on instance termination
Status in OpenStack Compute (Nova):
Fix Released
Status in OpenStack Compute (nova) folsom series:
In Progress
Bug description:
On rare occasion we have noticed that using nova-network and the
VlanManage fixed_ip aren't always marked as free during instance
termination until the _disassociate_stale_fixed_ips periodic job is
run.
The issue occurs as a result of dnsmasq is restarted. On restart the
nova-dhcpbridge command is called with the init arguement to populate
the dnsmasq lease DB. The lease time, is presently being calculated by
taking instances.updated_at or instances.created_at and adding
CONF.dhcp_lease_time. Unfortunately these fields are not updated by
normal DHCP actions. At dnsmasq start time the old leases are loaded
and immediately expired. As a result of this nova-dhcpbridge is called
with the del action and fixed_ips.leased is marked as 0 in the DB even
though a VM has a valid lease.
If a termination is issued while in this state dnsmasq will receive
the release packet and drop it claiming the lease is unknown. As a
result nova-dhcpbridge is not called to free the lease in the DB and
the IP remains in a partially freed state until the
_disassociate_stale_fixed_ips periodic job is run.
During normal DHCP operations the fixed_ips.updated_at field is
updated on a lease request or renewal. As such the dnsmasq lease DB
should be initialized from fixed_ips.updated_at or
fixed_ips.created_at instead of the values from the instances table.
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