Distributed_Applications.org
Table of Contents
distributed application 某节点挂了后，此种application 会在另外一个节点上启动
http://www.erlang.org/doc/design_principles/distributed_applications.html
erl -name c@l92.168.0.44 -config c.config
erl -name c2@l92.168.0.44 -config c2.config
erl -name c3@l92.168.0.44 -config c3.config
erl -name emacs@l92.168.0.44 -config master.config
distributed = [{Application, [Timeout,] NodeDesc}]
NodeDesc = [Node | {Node,…,Node}]
NodeDesc 表示此种Application可以在哪些节点上启动，优先级按NodeDesc[]中出现的顺序而定，但在{} 中的节点优先级相同
比如:
{distributed, [{game_log_server, 5000, ['emacs@192.168.0.44', {'c@192.168.0.44','c2@192.168.0.44','c3@192.168.0.44' }]}]}
game_log_server 会优先在'emacs@192.168.0.44'上启动，当'emacs@192.168.0.44'当掉后，会从{'c@192.168.0.44','c2@192.168.0.44','c3@192.168.0.44' }
中选择一个节点，在此节点上启动game_log_server application
Timeout
表示等待多少ms 才决定在其他节点上来启动此 application(即当前节点或许会在Timeout时间内重启成功。)
sync_nodes_mandatory = [Node]
Specifies which other nodes must be started (within the timeout specified by sync_nodes_timeout.
sync_nodes_optional = [Node]
Specifies which other nodes can be started (within the timeout specified by sync_nodes_timeout.
sync_nodes_timeout = integer() | infinity
Specifies how many milliseconds to wait for the other nodes to start.
When started, the node will wait for all nodes specified by sync_nodes_mandatory and sync_nodes_optional to come up
在启动当前节点的过程中，会等待 sync_nodes_mandatory 与 sync_nodes_optional属性中指定的节点启动后才启动,如果sync_nodes_mandatory
中有任一节点启动失败，则此停止此节点的启动
所有这些节点中
distributed and sync_nodes_timeout,两属性的值必须相同.
当所有distributed属性中指定的节点启动成功后，此 application会首先在emacs@192.168.0.44上启动
application:start(Application)
Module:start(normal, StartArgs)
当 emacs@192.168.0.44 当掉后,首先会尝试在等5000ms 让 emacs@192.168.0.44重启。
application会在新的节点上以
Module:start(normal, StartArgs)的方式重启，
例外是如果此 application 定义的tart_phases(http://www.erlang.org/doc/design_principles/included_applications.html)
则 Module:start({failover, Node}, StartArgs)
如果 emacs@192.168.0.44重启了。则此时 Takeover 事件会发生，即此 application会在 emacs@192.168.0.44 上重启，而 在old node
上stop
Module:start({takeover, Node}, StartArgs)
- master.config
[{kernel, [{distributed, [{game_log_server, 5000, ['emacs@192.168.0.44', {'c@192.168.0.44','c2@192.168.0.44' }]}]}, {sync_nodes_mandatory, ['c@192.168.0.44','c2@192.168.0.44' ]}, % mandatory托管 {sync_nodes_timeout, 5000} ] } ]. - c.config
%% http://www.erlang.org/doc/design_principles/distributed_applications.html %% erl -name emacs@l92.168.0.44 -config master.config %% erl -name c@l92.168.0.44 -config c.config %% erl -name c2@l92.168.0.44 -config c2.config %% erl -name c3@l92.168.0.44 -config c3.config [{kernel, [{distributed, [{game_log_server, 5000, ['emacs@192.168.0.44', {'c@192.168.0.44','c2@192.168.0.44' }]}]}, {sync_nodes_mandatory, ['emacs@192.168.0.44','c2@192.168.0.44' ]}, {sync_nodes_timeout, 5000} ] } ].%% http://www.erlang.org/doc/design_principles/distributed_applications.html %% erl -name emacs@l92.168.0.44 -config master.config %% erl -name c@l92.168.0.44 -config c.config %% erl -name c2@l92.168.0.44 -config c2.config %% erl -name c3@l92.168.0.44 -config c3.config [{kernel, [{distributed, [{game_log_server, 5000, ['emacs@192.168.0.44', {'c@192.168.0.44','c2@192.168.0.44' }]}]}, {sync_nodes_mandatory, ['c@192.168.0.44','emacs@192.168.0.44' ]}, {sync_nodes_timeout, 5000} ] } ].