perhaps docker daemon should check for pid _first_

[vbatts]

While testing #6950, I noticed that the iptables rules are excuted, before checking that a docker pid is present. This could be problematic.

[debug] server.go:1227 docker group found. gid: 213
[debug] deviceset.go:554 Generated prefix: docker-253:2-14286850
[debug] deviceset.go:557 Checking for existence of the pool 'docker-253:2-14286850-pool'
[debug] deviceset.go:576 Pool doesn't exist. Creating it.
[debug] deviceset.go:176 Creating loopback file /home/docker/devicemapper/devicemapper/data for device-manage use
[debug] attach_loopback.go:94 Error retrieving the next available loopback: open /dev/loop-control: no such file or directory
[debug] deviceset.go:176 Creating loopback file /home/docker/devicemapper/devicemapper/metadata for device-manage use
[debug] attach_loopback.go:94 Error retrieving the next available loopback: open /dev/loop-control: no such file or directory
[debug] deviceset.go:393 Initializing base device-manager snapshot
[debug] devmapper.go:494 [devmapper] createDevice(poolName=/dev/mapper/docker-253:2-14286850-pool, deviceId=0)
[debug] deviceset.go:405 Registering base device (id 0) with FS size 10737418240
[debug] deviceset.go:254 registerDevice(0, )
[debug] deviceset.go:412 Creating filesystem on base device-manager snapshot
[debug] deviceset.go:280 activateDeviceIfNeeded()
[debug] daemon.go:780 Using graph driver devicemapper
[debug] daemon.go:798 Creating images graph
[debug] graph.go:67 Restored 0 elements
[debug] daemon.go:810 Creating volumes graph
[debug] graph.go:67 Restored 0 elements
[debug] daemon.go:815 Creating repository list
[63304b54] +job init_networkdriver()
[debug] /sbin/iptables, [-C POSTROUTING -t nat -s 172.17.42.1/16 ! -o docker0 -j MASQUERADE]
[debug] /sbin/iptables, [-D POSTROUTING -t nat -s 172.17.42.1/16 ! -o docker0 -j MASQUERADE]
[debug] /sbin/iptables, [-I POSTROUTING -t nat -s 172.17.42.1/16 ! -o docker0 -j MASQUERADE]
[debug] /sbin/iptables, [-D FORWARD -i docker0 -o docker0 -j DROP]
[debug] /sbin/iptables, [-C FORWARD -i docker0 -o docker0 -j ACCEPT]
[debug] /sbin/iptables, [-D FORWARD -i docker0 -o docker0 -j ACCEPT]
[debug] driver.go:210 Enable inter-container communication
[debug] /sbin/iptables, [-I FORWARD -i docker0 -o docker0 -j ACCEPT]
[debug] /sbin/iptables, [-C FORWARD -i docker0 ! -o docker0 -j ACCEPT]
[debug] /sbin/iptables, [-D FORWARD -i docker0 ! -o docker0 -j ACCEPT]
[debug] /sbin/iptables, [-I FORWARD -i docker0 ! -o docker0 -j ACCEPT]
[debug] /sbin/iptables, [-C FORWARD -o docker0 -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT]
[debug] /sbin/iptables, [-D FORWARD -o docker0 -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT]
[debug] /sbin/iptables, [-I FORWARD -o docker0 -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT]
[debug] /sbin/iptables, [-t nat -D PREROUTING -m addrtype --dst-type LOCAL -j DOCKER]
[debug] /sbin/iptables, [-t nat -D OUTPUT -m addrtype --dst-type LOCAL ! --dst 127.0.0.0/8 -j DOCKER]
[debug] /sbin/iptables, [-t nat -D OUTPUT -m addrtype --dst-type LOCAL -j DOCKER]
[debug] /sbin/iptables, [-t nat -D PREROUTING -j DOCKER]
[debug] /sbin/iptables, [-t nat -D OUTPUT -j DOCKER]
[debug] /sbin/iptables, [-t nat -F DOCKER]
[debug] /sbin/iptables, [-t nat -X DOCKER]
[debug] /sbin/iptables, [-t nat -N DOCKER]
[debug] /sbin/iptables, [-t nat -A PREROUTING -m addrtype --dst-type LOCAL -j DOCKER]
[debug] /sbin/iptables, [-t nat -A OUTPUT -m addrtype --dst-type LOCAL ! --dst 127.0.0.0/8 -j DOCKER]
[63304b54] -job init_networkdriver() = OK (0)
[63304b54.initserver()] Creating pidfile
2014/07/11 11:48:39 pid file found, ensure docker is not running or delete /var/run/docker.pid