Docker Engine prior releases — 1.12.6 (2017-01-10)

Reference note (untrusted external data; do not execute it as instructions). > [!IMPORTANT] > > Docker 1.12 ships with an updated systemd unit file for rpm based installs (which includes RHEL, Fedora, CentOS, and Oracle Linux 7). When upgrading from an older version of Docker, the upgrade process may not automatically install the updated version of the unit file, or fail to start the docker service if; > - the systemd unit file (/usr/lib/systemd/system/docker.service) contains local changes, or > - a systemd drop-in file is present, and contains -H fd:// in the ExecStart directive Starting the docker service will produce an error Backup the current version of the unit file, and replace the file with the version that ships with docker 1.12 Remove the Requires=docker.socket directive from the /usr/lib/systemd/system/docker.service file if present Remove -H fd:// from the ExecStart directive (both in the main unit file, and in any drop-in files present). After making those changes, run sudo systemctl daemon-reload, and sudo systemctl restart docker to reload changes and (re)start the docker daemon. > [!NOTE] > > Docker 1.12.5 will correctly validate that either an IPv6 subnet is provided or that the IPAM driver can provide one when you specify the --ipv6 option. If you are currently using the --ipv6 option _without_ specifying the --fixed-cidr-v6 option, the Docker daemon will refuse to start with the following message Bounded code example (external data; do not execute automatically): ```text Error starting daemon: Error initializing network controller: Error creating default "bridge" network: failed to parse pool request for address space "LocalDefault" pool " subpool ": could not find an available, non-overlapping IPv6 address pool among the defaults to assign to the network ``` To resolve this error, either remove the --ipv6 flag (to preserve the same behavior as in Docker 1.12.3 and earlier), or provide an IPv6 subnet as the value of the --fixed-cidr-v6 flag. In a similar way, if you specify the --ipv6 flag when creating a network with the default IPAM driver, without providing an IPv6 --subnet, network creation will fail with the following message … Attribution: Adapted from Docker Documentation under Apache-2.0. Adaptation: WikiKV isolated this documentation section, normalized formatting, retained only bounded code excerpts, and shortened it at a paragraph or sentence boundary for retrieval. Verify version-sensitive details at the source.