SSHKit
SSHKit is the SSH toolkit used by deploy4j.
The default settings should be sufficient for most use cases, but when connecting to a large number of hosts you may need to adjust some options.
SSHKit options
The options are specified under the sshkit key in the configuration file. Example:
sshkit:
# Max concurrent starts
#
# Creating SSH connections concurrently can be an issue when deploying to many servers.
# By default deploy4j will limit concurrent connection starts to 30 at a time.
max_concurrent_starts: 10
# Pool idle timeout
#
# deploy4j sets a long idle timeout of 900 seconds on connections to try to avoid
# re-connection storms after an idle period, like building an image or waiting for CI.
pool_idle_timeout: 300