apache mesos 入门（4）——mesos中的资源

mesos根据角色（ROLE）在不同的framework之间分配资源，在启动master时可以指定系统中的角色和每种角色的权重，例如：

mesos-master --ip=127.0.0.1 --work_dir=/var/lib/mesos --roles=qarole,devrole --weights='qarole=1,devrole=3'

指定了两种角色parole和devrole，权重分别是1和3.

在设置FrameworkInfo时可以设置对应的角色

/**
* Describes a framework.
*/
message FrameworkInfo {
// Used to determine the Unix user that an executor or task should
// be launched as. If the user field is set to an empty string Mesos
// will automagically set it to the current user.
required string user = 1;

// Name of the framework that shows up in the Mesos Web UI.
required string name = 2;

// Note that 'id' is only available after a framework has
// registered, however, it is included here in order to facilitate
// scheduler failover (i.e., if it is set then the
// MesosSchedulerDriver expects the scheduler is performing
// failover).
optional FrameworkID id = 3;

// The amount of time (in seconds) that the master will wait for the
// scheduler to failover before it tears down the framework by
// killing all its tasks/executors. This should be non-zero if a
// framework expects to reconnect after a failure and not lose its
// tasks/executors.
//
// NOTE: To avoid accidental destruction of tasks, production
// frameworks typically set this to a large value (e.g., 1 week).
optional double failover_timeout = 4 [default = 0.0];

// If set, framework pid, executor pids and status updates are
// checkpointed to disk by the slaves. Checkpointing allows a
// restarted slave to reconnect with old executors and recover
// status updates, at the cost of disk I/O.
optional bool checkpoint = 5 [default = false];

<span style="color:#ff0000;">  // Used to group frameworks for allocation decisions, depending on
// the allocation policy being used.
optional string role = 6 [default = "*"];</span>

// Used to indicate the current host from which the scheduler is
// registered in the Mesos Web UI. If set to an empty string Mesos
// will automagically set it to the current hostname if one is
// available.
optional string hostname = 7;

// This field should match the credential's principal the framework
// uses for authentication. This field is used for framework API
// rate limiting and dynamic reservations. It should be set even
// if authentication is not enabled if these features are desired.
optional string principal = 8;

// This field allows a framework to advertise its web UI, so that
// the Mesos web UI can link to it. It is expected to be a full URL,
// for example http://my-scheduler.example.com:8080/. optional string webui_url = 9;

message Capability {
enum Type {
// Receive offers with revocable resources. See 'Resource'
// message for details.
// TODO(vinod): This is currently a no-op.
REVOCABLE_RESOURCES = 1;

// Receive the TASK_KILLING TaskState when a task is being
// killed by an executor. The executor will examine this
// capability to determine whether it can send TASK_KILLING.
TASK_KILLING_STATE = 2;
}

required Type type = 1;
}

// This field allows a framework to advertise its set of
// capabilities (e.g., ability to receive offers for revocable
// resources).
repeated Capability capabilities = 10;

// Labels are free-form key value pairs supplied by the framework
// scheduler (e.g., to describe additional functionality offered by
// the framework). These labels are not interpreted by Mesos itself.
// Labels should not contain duplicate key-value pairs.
optional Labels labels = 11;
}

slave启动时会检测当前节点的资源情况，包括cpu、内存、磁盘等，slave默认会预留1G（或者50%）的内存，5G（或者50%）的磁盘以保证自己及操作系统的正常运行，剩下的资源会上报master以供调度。当然也可以手动指定应该上报的资源量，例如，

mesos-slave --master=127.0.0.1:5050 --resources='cpus:4;mem:8192;ports:[1000-5000,31000-32000];'

slave还可以静态的设置各个角色的资源量，例如：

mesos-slave --master=127.0.0.1:5050 --resources='cpus(prod):1;mem(prod):4096;cpus(qa):2;mem(qa):1024;cpus:13;mem:11264' --attributes='operating_system:ubuntu;cpu_class:haswell;zone:us_east;rack:22'

其中prod角色：1cpu、4096内存

qa角色：2cpu、1024内存

默认角色：13cpu、11264内存

除了上报slave节点的资源情况，也可以标记当前节点的一些属性以供scheduler使用，比如是否ssd硬盘，操作系统类型等

mesos-slave --master=127.0.0.1:5050 --resources='cpus:4;mem:8192;ports:[1000-5000,31000-32000];' --attributes='operating_system:ubuntu;cpu_class:haswell;zone:us_east;rack:22'