Ucloud » History » Revision 3
Revision 2 (Ahmed Bilal, 07/01/2019 02:03 PM) → Revision 3/16 (Ahmed Bilal, 07/01/2019 02:03 PM)
h1. ucloud (To Be Continued)
h2. ucloud-api
Outside world (indirect) communication with the internal systems.
Its responsibilities are
* Create VM *(Done)* POST _/vm/create_
<pre><code class="javascript">
{
"name": "username",
"realm": "user_realm",
"seed": "user_seed",
"specs": {
"cpu": 16,
"ram": 256,
"hdd": 2000,
"ssd": 256
}
}
</code></pre>
* Delete VM *(Done)* POST _/vm/delete_
<pre><code class="javascript">
{
"name": "username",
"realm": "user_realm",
"seed": "user_seed",
"vmid": "id_of_virtual_machine"
}
</code></pre>
* Status VM *(Done)* GET _/vm/status_
<pre><code class="javascript">
{
"id": "id_of_virtual_machine"
}
</code></pre>
* Create new network
* Attach network to VM
* Detach network from VM
* Delete network
h2. ucloud-scheduler
It schedules/reschedules VM that are created using ucloud-api. How does it schedules? It does by watching any changes under the _/v1/vm/_ prefix. Basically, it deals with two ETCD entries
1. Virtual Machines Entries that looks like
<pre><code class="javascript">
/v1/vm/1
{
"owner": "ahmedbilal-admin",
"specs": {
"cpu": 20,
"ram": 2,
"hdd": 10,
"ssd": "sdd": 10
},
"hostname": "",
"status": "REQUESTED_NEW"
}
</code></pre>
2. Hosts Entries that look like
<pre><code class="javascript">
/v1/host/1
{
"cpu": 32,
"ram": 128,
"hdd": 1024,
"ssd": "sdd": 0
"status": "UP"
}
</code></pre>
It loop through list of host entries found under _/v1/host/_ and check whether we can run the incoming VM on that host. if we can, then it (ucloud-scheduler) sets the hostname key of incoming VM to that host. Suppose, our scheduler decides that we can run the earlier shown VM _/v1/vm/1_ on _/v1/host/1_. Then, our updated entry would look like
<pre><code class="javascript">
/v1/vm/1
{
"owner": "ahmedbilal-admin",
"specs": {
"cpu": 20,
"ram": 2,
"hdd": 10,
"ssd": "sdd": 10
},
"hostname": "/v1/host/1",
"status": "REQUESTED_NEW"
}
</code></pre>
*Note* the hostname key/value pair.
h2. ucloud-vm
It is responsible for creating (running) / deleting (stopping) / monitoring virtual machines
It watches the _/v1/vm/_ prefix for any changes like (Virtual Machines with status like *SCHEDULED_DEPLOY* or *REQUEST_DELETE*.
On, *SCHEDULED_DEPLOY* it creates the VM and run it. On, *REQUEST_DELETE* it stops the VM.
It is also responsible for monitoring VM statues i.e whether they are RUNNING or KILLED (in action). If a VM is killed we put that in log file, notify system administrator and restart it.