Added host switch

cockroach.service

@@ -6,6 +6,8 @@ WantedBy=multi-user.target
 
 [Service]
 ExecStartPre=/bin/bash -c "test -f /etc/cockroachdb/hosts && (/bin/systemctl set-environment JOIN_SWITCH=--join=$(test -f /etc/cockroachdb/hosts && cat /dev/null /etc/cockroachdb/hosts)) || exit 0"
+ExecStartPre=/bin/bash -c "test -f /etc/cockroachdb/host && (/bin/systemctl set-environment HOST_SWITCH=--host=$(test -f /etc/cockroachdb/host && cat /dev/null /etc/cockroachdb/host)) || exit 0"
+
 ExecStart=/usr/local/bin/cockroach start --certs-dir=/etc/cockroachdb/certs \
  --store=/var/data/cockroachdb/ \
  --cache=.40 \
@@ -16,7 +18,7 @@ ExecStart=/usr/local/bin/cockroach start --certs-dir=/etc/cockroachdb/certs \
  --http-port=7005 \
  --logtostderr=ERROR \
  --log-dir=/var/logs/cockroachdb \
- $JOIN_SWITCH
+ $JOIN_SWITCH $HOST_SWITCH
 
 ExecStop=/usr/local/bin/cockroach quit --certs-dir=/etc/cockroachdb/certs
 SyslogIdentifier=cockroachdb