From the systemd man page:
Use "${FOO}" as part of a word, or as a word of its own, on the command
line, in which case it will be
replaced by the value of the environment variable including
all whitespace it contains, resulting in a single argument.
Use "$FOO" as a separate word on the
command line, in which case it will be replaced
by the value of the environment variable split at
whitespace, resulting in zero or more arguments.
Since we want people to be able to use these for multiple arguments we
need to make sure we don't use {} around the env vars...
Some image based OS do not allow writing to /. Since the kubelet looks
for .dockercfg files in the working dir and uses / as the working dir,
this means one can never set a .dockercfg on those distros. This moves
the kubelet working dir to /var/lib/kubelet, where the kubelet naturally
does its work.
Some distros, include RHEL and Fedora, are doing away with the docker
socket by default in systemd units, for security reasons. Instead rely
on the docker.service being started instead of socket activation.
The example systemd services files, environment files, and the fedora
manual config doc all used numerous references to minion_. Many of
these are better named kubelet_. Convert them.
Eric Paris