dockerctl backup fails if containers are already paused

dockerctl backup attempts to pause the containers, but if the containers are already paused (for example from a previous failed backup attempt) dockerctl backup will fail.

What I'd expect: Either dockerctl backup should recognize that the containers are already paused and continue with the backup resuming the contains when finished or if for some reason this behavior is necessary then it should check the container status before starting the backup procedure so that the failure in immediate rather than half way through the lengthy backup procedure.

[root@fuel ~]# /usr/bin/dockerctl backup /var/log/fueldocker
Reading container data...
Committing fuel-core-8.0-mcollective...
db3bc3312d4cc0fccb4c20728209fb788901ccd45ded63c218e2da37964e0c45
Committing fuel-core-8.0-cobbler...
d6533f91aa299309d996c1d8d8b723a6d19521f7bcc41e9380ed61fcade717a5
Committing fuel-core-8.0-nginx...
077302afd1758ae9475dfc0d90344418b6cf8214a576bc9b37986e29ab434698
Committing fuel-core-8.0-ostf...
4e357316cfd3b07432fc0bda2c0520550fc046be6a44ffcb9d068761979a229a
Committing fuel-core-8.0-nailgun...
db703ca5d2e85f411a2263793342391dc477265f1723851255329a5bfcf301c8
Committing fuel-core-8.0-rsyslog...
02a4171d6c3e32bc56f623fb9f0954601be35aa913088a48e6b1759620407ad6
Committing fuel-core-8.0-astute...
098fdf5f47d73522c821a332687fedb1f17e8232fb4cfe96d46b55581fbc4ee5
Committing fuel-core-8.0-rsync...
1a393b8220fe60e31768622a34f0bca800539c879f4c42c11426c1cd8b997442
Committing fuel-core-8.0-keystone...
10d17561f1f821089f77df332e8cde9b772bb6d551a96b88b1f90ce6f83c07ee
Committing fuel-core-8.0-rabbitmq...
28372785bfd3ebd270160cb61d77c8ed71802c8949402a6380fa0cdaf24e0e5a
Committing fuel-core-8.0-postgres...
575d3fa14ade66a579b2ad392d9c4b5fe16cc7e1f8a45ffa7d8ccb61bfdf37ab
Saving containers to combined archive...
time="2016-07-18T01:13:18Z" level=debug msg="[stream] End of stdout"
Cleaning up temporary images...
Untagged: fuel/postgres_8.0_2016-07-18_0107:latest
Deleted: 575d3fa14ade66a579b2ad392d9c4b5fe16cc7e1f8a45ffa7d8ccb61bfdf37ab
Untagged: fuel/rabbitmq_8.0_2016-07-18_0107:latest
Deleted: 28372785bfd3ebd270160cb61d77c8ed71802c8949402a6380fa0cdaf24e0e5a
Untagged: fuel/keystone_8.0_2016-07-18_0107:latest
Deleted: 10d17561f1f821089f77df332e8cde9b772bb6d551a96b88b1f90ce6f83c07ee
Untagged: fuel/rsync_8.0_2016-07-18_0107:latest
Deleted: 1a393b8220fe60e31768622a34f0bca800539c879f4c42c11426c1cd8b997442
Untagged: fuel/astute_8.0_2016-07-18_0107:latest
Deleted: 098fdf5f47d73522c821a332687fedb1f17e8232fb4cfe96d46b55581fbc4ee5
Untagged: fuel/rsyslog_8.0_2016-07-18_0107:latest
Deleted: 02a4171d6c3e32bc56f623fb9f0954601be35aa913088a48e6b1759620407ad6
Untagged: fuel/nailgun_8.0_2016-07-18_0107:latest
Deleted: db703ca5d2e85f411a2263793342391dc477265f1723851255329a5bfcf301c8
Untagged: fuel/ostf_8.0_2016-07-18_0107:latest
Deleted: 4e357316cfd3b07432fc0bda2c0520550fc046be6a44ffcb9d068761979a229a
Untagged: fuel/nginx_8.0_2016-07-18_0107:latest
Deleted: 077302afd1758ae9475dfc0d90344418b6cf8214a576bc9b37986e29ab434698
Untagged: fuel/cobbler_8.0_2016-07-18_0107:latest
Deleted: d6533f91aa299309d996c1d8d8b723a6d19521f7bcc41e9380ed61fcade717a5
Untagged: fuel/mcollective_8.0_2016-07-18_0107:latest
Deleted: db3bc3312d4cc0fccb4c20728209fb788901ccd45ded63c218e2da37964e0c45
Pausing containers...
Error response from daemon: Cannot pause container 8f4a682011e8: Container 8f4a682011e8a4ae699341ad6e041c1debda6e5e80e1c02545957932c0cb836c is already paused
Error: failed to pause containers: [8f4a682011e8]
Error response from daemon: Cannot pause container 7d9c5f6dee19: Container 7d9c5f6dee19bc87df27345e878a39a91ff1e0e195bdafe1d8119b0746ef1dfe is already paused
Error: failed to pause containers: [7d9c5f6dee19]
Error response from daemon: Cannot pause container 1ce7b238fb66: Container 1ce7b238fb6629f71e65fd69574a40b162debc58b8204f12f641000744e9b435 is already paused
Error: failed to pause containers: [1ce7b238fb66]
Error response from daemon: Cannot pause container dbede3985db4: Container dbede3985db41e42192aa623fb3914e68bca783c33fb62f2ed38151c4e967216 is already paused
Error: failed to pause containers: [dbede3985db4]
Error response from daemon: Cannot pause container 3f0453364c84: Container 3f0453364c845d57ad214be74cb78aa5ea73ef7e3f8fd1cbed2574e79ca32134 is already paused
Error: failed to pause containers: [3f0453364c84]
Error response from daemon: Cannot pause container 8b0b08ae4135: Container 8b0b08ae41355e3d42f5b0dd5463f10c3d24968bf4f312f8e795723c90c10370 is already paused
Error: failed to pause containers: [8b0b08ae4135]
Error response from daemon: Cannot pause container 880325d381e9: Container 880325d381e9d4395e841d7691c48decfa4f5267bd3350158de4c50c0fb0c75a is already paused
Error: failed to pause containers: [880325d381e9]
Error response from daemon: Cannot pause container bc481b553b4a: Container bc481b553b4a7d78e99049075a4a3b3e9f51e2f9c24c4c52032bb479d87f5e2f is already paused
Error: failed to pause containers: [bc481b553b4a]
Error response from daemon: Cannot pause container 24ec877bdbc1: Container 24ec877bdbc189d6c23de4071d82cf83dffbeb31af58d2a038ad0a8925e7dd31 is already paused
Error: failed to pause containers: [24ec877bdbc1]
Error response from daemon: Cannot pause container 9f398899266e: Container 9f398899266edab33a8171733eb9a9c68d555cb5b2030a10ca07e2bdffad6cf0 is already paused
Error: failed to pause containers: [9f398899266e]
Error response from daemon: Cannot pause container 11626b9707f9: Container 11626b9707f9f81fc15cdfea760584e30ec9c41ebd8cd9a13e18a202864530d4 is already paused
Error: failed to pause containers: [11626b9707f9]
Backup failed!