是否可以在调试挂钩窗口中跟踪添加关系挂钩？是否需要设置特定的环境变量才能成功？
我的 juju-core 版本是 1.13.3。
我想观察 cloud-compute-relation-changed 钩子的运行情况，因为我在尝试添加 nova-cloud-controller 和 nova-compute 之间的关系时看到了这个失败：
amcet:2013-09-12 20:18:39 INFO juju context.go:221 worker/uniter: HOOK getaddrinfo xxn79: Name or service not known
amcet:2013-09-12 20:18:39 INFO juju server.go:105 worker/uniter/jujuc: running hook tool "juju-log" ["nova-cloud-controller ERROR: nova-cloud-controller: Couldn't obtain SSH host key from xxn79."]
amcet:2013-09-12 20:18:39 DEBUG juju server.go:106 worker/uniter/jujuc: hook context id "nova-cloud-controller/0:cloud-compute-relation-changed:4369123461286104487"; dir "/var/lib/juju/agents/unit-nova-cloud-controller-0/charm"
amcet:2013-09-12 20:18:39 INFO juju juju-log.go:64 nova-cloud-controller/0 cloud-compute:32: nova-cloud-controller ERROR: nova-cloud-controller: Couldn't obtain SSH host key from xxn79.
amcet:2013-09-12 20:18:39 ERROR juju uniter.go:352 …