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Ucloud » History » Revision 5

Revision 4 (Ahmed Bilal, 07/02/2019 09:17 AM) → Revision 5/16 (Ahmed Bilal, 07/02/2019 09:17 AM)

h1. ucloud (To Be Continued) 

 h2. Requirements 

 
 1. Python 3.7, pip, pipenv 
 2. etcd 
 3. ceph 

 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": 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": 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": 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.