Not a constraint but you can use the availability zones to achieve this.
root@juju01:~# juju add-machine zone=cluster05 created machine 3 root@juju01:~# juju status Model Controller Cloud/Region Version SLA Timestamp default nsec-default nsec/default 2.9.29 unsupported 17:32:00Z
Machine State DNS Inst id Series AZ Message 3 pending 240.28.0.167 juju-378e3e-3 focal Running
root@cluster01:~# lxc list juju-378e3e-3 +---------------+---------+---------------------+------+-----------+-----------+-----------+ | NAME | STATE | IPV4 | IPV6 | TYPE | SNAPSHOTS | LOCATION | +---------------+---------+---------------------+------+-----------+-----------+-----------+ | juju-378e3e-3 | RUNNING | 240.28.0.167 (eth0) | | CONTAINER | 0 | cluster05 | +---------------+---------+---------------------+------+-----------+-----------+-----------+
Not a constraint but you can use the availability zones to achieve this.
root@juju01:~# juju add-machine zone=cluster05
created machine 3
root@juju01:~# juju status
Model Controller Cloud/Region Version SLA Timestamp
default nsec-default nsec/default 2.9.29 unsupported 17:32:00Z
Machine State DNS Inst id Series AZ Message
3 pending 240.28.0.167 juju-378e3e-3 focal Running
root@cluster01:~# lxc list juju-378e3e-3 ------- --+---- -----+- ------- ------- ------+ ------+ ------- ----+-- ------- --+---- ------- + ------- --+---- -----+- ------- ------- ------+ ------+ ------- ----+-- ------- --+---- ------- + ------- --+---- -----+- ------- ------- ------+ ------+ ------- ----+-- ------- --+---- ------- +
+------
| NAME | STATE | IPV4 | IPV6 | TYPE | SNAPSHOTS | LOCATION |
+------
| juju-378e3e-3 | RUNNING | 240.28.0.167 (eth0) | | CONTAINER | 0 | cluster05 |
+------