Extra hosts (`extra_hosts` in compose-file, or `--hosts` in services) adds
custom host/ip mappings to the container's `/etc/hosts`.
The current implementation used a `map[string]string{}` as intermediate
storage, and sorted the results alphabetically when converting to a service-spec.
As a result, duplicate hosts were removed, and order of host/ip mappings was not
preserved (in case the compose-file used a list instead of a map).
According to the **host.conf(5)** man page (http://man7.org/linux/man-pages/man5/host.conf.5.html)
multi Valid values are on and off. If set to on, the resolver
library will return all valid addresses for a host that
appears in the /etc/hosts file, instead of only the first.
This is off by default, as it may cause a substantial
performance loss at sites with large hosts files.
Multiple entries for a host are allowed, and even required for some situations,
for example, to add mappings for IPv4 and IPv6 addreses for a host, as illustrated
by the example hosts file in the **hosts(5)** man page (http://man7.org/linux/man-pages/man5/hosts.5.html):
# The following lines are desirable for IPv4 capable hosts
127.0.0.1 localhost
# 127.0.1.1 is often used for the FQDN of the machine
127.0.1.1 thishost.mydomain.org thishost
192.168.1.10 foo.mydomain.org foo
192.168.1.13 bar.mydomain.org bar
146.82.138.7 master.debian.org master
209.237.226.90 www.opensource.org
# The following lines are desirable for IPv6 capable hosts
::1 localhost ip6-localhost ip6-loopback
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
This patch changes the intermediate storage format to use a `[]string`, and only
sorts entries if the input format in the compose file is a mapping. If the input
format is a list, the original sort-order is preserved.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
The `--host-add` flag adds a new `host:ip` mapping. Even though
adding an entry is idempotent (adding the same mapping multiple
times does not update the service's definition), it does not
_update_ an existing mapping with a new IP-address (multiple
IP-addresses can be defined for a host).
This patch removes the "or update" part from the flag's
description.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
golang:1.8.4-alpine does not have multi-arch images available in the
manifest. (s390x, ppc64le, etc.)
This makes it so that if you are trying to compile on different
arches you aren't forced to have to write your own Dockerfile and can
instead use the one bundled with the CLI repo.
Signed-off-by: Eli Uriegas <eli.uriegas@docker.com>
and enable the new WarnUnmatchedDirective to warn if a nolint is unnecessary.
remove some unnecessary nolint
Signed-off-by: Daniel Nephin <dnephin@docker.com>
The example in the documentation used "runc", which is a
reserved runtime name (as it's the default).
This patch updates the example, and uses a different name.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Since the API and the CLI both have a "Usage" field for memory, clarify
that the CLI does additional calculations to avoid confusion of API
consumers.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
The experimental `docker build --squash` feature has a number
of limitations. For most use-cases, multi-stage builds are
a better alternative.
This patch lists the known limitations, and adds a link to
multi-stage builds.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Sebastiaan van Stijn