pub fn upgrade(names: &[String], all: bool, binary: Option<&Path>) -> Result<()>Expand description
Push binary to names (or every registered host, with all) over the
control channel and re-verify each with selfcheck. The binary is read
once and streamed unchanged to every target. A per-host failure is
printed and does not abort the rest — the fleet-wide --all case must
finish attempting every host before this returns a non-zero error, so a
script driving it can detect a partial upgrade without losing the hosts
that did succeed.