[kea-dev] [0.9.1-beta1] Issue with config reload and IPv4 sockets

[Tomek Mrugalski]

On 23/02/15 16:34, Chaigneau, Nicolas wrote:
> Hello,
> 
> When attempting to reload Kea configuration through a HUP signal, for example with:
> 
> kill -HUP $(pidof kea-dhcp4)
> 
> The log file shows the following errors:
> 
> 	2015-02-23 16:29:08.944 INFO  [kea-dhcp4.dhcp4/17947] DHCP4_DYNAMIC_RECONFIGURATION initiate server reconfiguration using file: /mnt/wifi/users/NCH/src-owa/src-kea-qualif/etc/kea1.conf, after receiving SIGHUP signal
> 	2015-02-23 16:29:08.945 INFO  [kea-dhcp4.dhcpsrv/17947] DHCPSRV_CFGMGR_USE_ADDRESS listening on address 10.163.216.230, on interface eth0.102
> 	2015-02-23 16:29:08.945 INFO  [kea-dhcp4.dhcpsrv/17947] DHCPSRV_CFGMGR_SOCKET_TYPE_SELECT using socket type udp
> 	2015-02-23 16:29:08.945 INFO  [kea-dhcp4.dhcpsrv/17947] DHCPSRV_MEMFILE_DB opening memory file lease database: lfc-interval=60 name=/var/opt/data/flat/mwpdhcp/ramdisk1/kea1-leases4.csv persist=true type=memfile universe=4
> 	2015-02-23 16:29:08.946 INFO  [kea-dhcp4.dhcpsrv/17947] DHCPSRV_MEMFILE_LEASE_FILE_LOAD loading leases from file /var/opt/data/flat/mwpdhcp/ramdisk1/kea1-leases4.csv.2
> 	2015-02-23 16:29:08.946 INFO  [kea-dhcp4.dhcpsrv/17947] DHCPSRV_MEMFILE_LEASE_FILE_LOAD loading leases from file /var/opt/data/flat/mwpdhcp/ramdisk1/kea1-leases4.csv
> 	2015-02-23 16:29:08.946 INFO  [kea-dhcp4.dhcpsrv/17947] DHCPSRV_MEMFILE_LFC_SETUP setting up the Lease File Cleanup interval to 60 sec
> 	2015-02-23 16:29:08.946 INFO  [kea-dhcp4.dhcp4/17947] DHCP4_CONFIG_NEW_SUBNET a new subnet has been added to configuration: 10.164.0.0/15 with params: t1=900, t2=1575, valid-lifetime=1800
> 	2015-02-23 16:29:08.946 INFO  [kea-dhcp4.dhcp4/17947] DHCP4_CONFIG_COMPLETE DHCPv4 server has completed configuration: added IPv4 subnets: 1; DDNS: disabled
> 	2015-02-23 16:29:08.946 ERROR [kea-dhcp4.dhcp4/17947] DHCP4_CONFIG_LOAD_FAIL configuration error using file: /mnt/wifi/users/NCH/src-owa/src-kea-qualif/etc/kea1.conf, reason: Error while processing command 'config-reload':it is not allowed to set new packet filter when there are open IPv4 sockets - need to close them first, params: '{ "hooks-libraries": [ "/mnt/wifi/users/NCH/src-owa/src-kea-qualif/hooks/libdhcp_nch_hook.so" ], "interfaces-config": { "dhcp-socket-type": "udp", "interfaces": [ "eth0.102/10.163.216.230" ] }, "lease-database": { "lfc-interval": 60, "name": "/var/opt/data/flat/mwpdhcp/ramdisk1/kea1-leases4.csv", "persist": true, "type": "memfile" }, "rebind-timer": 1575, "renew-timer": 900, "subnet4": [ { "id": 1001, "pools": [ { "pool": "10.164.0.2 - 10.165.255.254" } ], "relay": { "ip-address": "10.163.216.250" }, "subnet": "10.164.0.0/15" } ], "valid-lifetime": 1800 }'
> 	2015-02-23 16:29:08.946 ERROR [kea-dhcp4.dhcp4/17947] DHCP4_DYNAMIC_RECONFIGURATION_FAIL dynamic server reconfiguration failed with file: /mnt/wifi/users/NCH/src-owa/src-kea-qualif/etc/kea1.conf
Nicolas and I looked into this matter further and it seems that the
problem is in CfgIface::openSockets. The code calls
iface_mgr.setMatchingPacketFilter() (line 77) before calling
closeSockets() (line 131). Inside setMatchingPacketFilter() there's a
call to setPacketFilter() which checks if there are open sockets and
throws if there are any.

The simplest solution will be to move the call to closeSockets() to some
place before the call to setMatchingPacketFilter().

I'll file in a ticket and develop the fix once I get back home, unless
someone else wants to fix this sooner.

On a related note, this bug makes kea reconfiguration unusable. This is
a regression (it used to be working in earlier kea versions). So I'd say
it's rather highly visible. Fortunately, it's easy to fix.

Also, we need to extend our tests to better check reconfiguration.

Tomek