docs(k8s): add k8s integration documentation in customizing schedulers

Author: Keerthan Mala

scheduler/k8s.py

@@ -39,13 +39,15 @@
       "replicas":$num,
       "selector":{
          "name":"$id",
-         "version":"$appversion"
+         "version":"$appversion",
+         "type":"$type"
       },
       "template":{
          "metadata":{
             "labels":{
                "name":"$id",
-               "version":"$appversion"
+               "version":"$appversion",
+               "type":"$type"
             }
          },
          "spec":{
@@ -78,7 +80,8 @@
         }
       ],
       "selector":{
-         "name":"$label"
+         "name":"$label",
+         "type":"$type"
       }
    }
 }'''
@@ -101,7 +104,7 @@ def __init__(self, target, auth, options, pkey):
         self.apiversion = "v1"
         self.conn = httplib.HTTPConnection(self.target+":"+self.port)
 
-    def _get_old_rc(self, name):
+    def _get_old_rc(self, name, app_type):
         con_app = httplib.HTTPConnection(self.target+":"+self.port)
         con_app.request('GET', '/api/'+self.apiversion +
                         '/namespaces/default/replicationcontrollers')
@@ -118,7 +121,8 @@ def _get_old_rc(self, name):
         exists = False
         prev_rc = []
         for rc in parsed_json['items']:
-            if 'name' in rc['metadata']['labels'] and name == rc['metadata']['labels']['name']:
+            if('name' in rc['metadata']['labels'] and name == rc['metadata']['labels']['name'] and
+               'type' in rc['spec']['selector'] and app_type == rc['spec']['selector']['type']):
                 exists = True
                 prev_rc = rc
                 break
@@ -154,7 +158,8 @@ def _get_rc_(self, name):
 
     def deploy(self, name, image, command, **kwargs):
         app_name = kwargs.get('aname', {})
-        old_rc = self._get_old_rc(app_name)
+        app_type = name.split(".")[1]
+        old_rc = self._get_old_rc(app_name, app_type)
         new_rc = self._create_rc(name, image, command, **kwargs)
         desired = int(old_rc["spec"]["replicas"])
         old_rc_name = old_rc["metadata"]["name"]
@@ -257,12 +262,12 @@ def _scale_app(self, name, num):
         self._scale_rc(js_template)
 
     def scale(self, name, image, command, **kwargs):
-        rc_name = name.split(".")[0]
+        rc_name = name.replace(".", "-")
         rc_name = rc_name.replace("_", "-")
         if not 200 <= self._get_rc_status(rc_name) <= 299:
             self.create(name, image, command, **kwargs)
             return
-        name = name.split(".")[0]
+        name = name.replace(".", "-")
         name = name.replace("_", "-")
         num = kwargs.get('num', {})
         js_template = self._get_rc_(name)
@@ -279,7 +284,7 @@ def _create_rc(self, name, image, command, **kwargs):
         app_name = kwargs.get('aname', {})
         app_type = name.split(".")[1]
         container_name = app_name+"-"+app_type
-        name = name.split(".")[0]
+        name = name.replace(".", "-")
         name = name.replace("_", "-")
         args = command.split()
 
@@ -292,6 +297,7 @@ def _create_rc(self, name, image, command, **kwargs):
         l["image"] = self.registry+"/"+image
         l['num'] = num
         l['containername'] = container_name
+        l['type'] = app_type
         template = string.Template(RC_TEMPLATE).substitute(l)
         js_template = json.loads(template)
         containers = js_template["spec"]["template"]["spec"]["containers"]
@@ -338,17 +344,36 @@ def _create_rc(self, name, image, command, **kwargs):
 
     def create(self, name, image, command, **kwargs):
         self._create_rc(name, image, command, **kwargs)
-        name = name.split(".")[0]
+        app_type = name.split(".")[1]
+        name = name.replace(".", "-")
         name = name.replace("_", "-")
         app_name = kwargs.get('aname', {})
         try:
-            self._create_service(name, app_name)
+            self._create_service(name, app_name, app_type)
         except Exception as e:
+            self._scale_app(name, 0)
             self._delete_rc(name)
             err = '{} (create): {}'.format(name, e)
             raise RuntimeError(err)
 
-    def _create_service(self, name, app_name):
+    def _get_service(self, name):
+        con_get = httplib.HTTPConnection(self.target+":"+self.port)
+        con_get.request('GET', '/api/'+self.apiversion+'/namespaces/default/services/'+name)
+        resp = con_get.getresponse()
+        reason = resp.reason
+        status = resp.status
+        data = resp.read()
+        con_get.close()
+        if not 200 <= status <= 299:
+            errmsg = "Failed to get Service: {} {} - {}".format(
+                status, reason, data)
+            raise RuntimeError(errmsg)
+        return (status, data, reason)
+
+    def _create_service(self, name, app_name, app_type):
+        random.seed(app_name)
+        app_id = random.randint(1, 100000)
+        appname = "app-"+str(app_id)
         actual_pod = {}
         for _ in xrange(300):
             status, data, reason = self._get_pods()
@@ -370,9 +395,8 @@ def _create_service(self, name, app_name):
         l["version"] = self.apiversion
         l["label"] = app_name
         l["port"] = port
-        random.seed(app_name)
-        app_id = random.randint(1, 100000)
-        l["name"] = "app-"+str(app_id)
+        l['type'] = app_type
+        l["name"] = appname
         template = string.Template(SERVICE_TEMPLATE).substitute(l)
         headers = {'Content-Type': 'application/json'}
         conn_serv = httplib.HTTPConnection(self.target+":"+self.port)
@@ -383,7 +407,27 @@ def _create_service(self, name, app_name):
         reason = resp.reason
         status = resp.status
         conn_serv.close()
-        if not 200 <= status <= 299:
+        if status == 409:
+            status, data, reason = self._get_service(appname)
+            srv = json.loads(data)
+            if srv['spec']['selector']['type'] == 'web':
+                return
+            srv['spec']['selector']['type'] = app_type
+            srv['spec']['ports'][0]['targetPort'] = port
+            headers = {'Content-Type': 'application/json'}
+            conn_scalepod = httplib.HTTPConnection(self.target+":"+self.port)
+            conn_scalepod.request('PUT', '/api/'+self.apiversion+'/namespaces/default/' +
+                                  'services/'+appname, headers=headers, body=json.dumps(srv))
+            resp = conn_scalepod.getresponse()
+            data = resp.read()
+            reason = resp.reason
+            status = resp.status
+            conn_scalepod.close()
+            if not 200 <= status <= 299:
+                errmsg = "Failed to update the Service:{} {} {} - {}".format(
+                    name, status, reason, data)
+                raise RuntimeError(errmsg)
+        elif not 200 <= status <= 299:
             errmsg = "Failed to create Service:{} {} {} - {}".format(
                      name, status, reason, data)
             raise RuntimeError(errmsg)
@@ -417,9 +461,10 @@ def _delete_rc(self, name):
 
     def destroy(self, name):
         """
-        Destroy a container
+        Destroy a the app
         """
-        name = name.split(".")[0]
+        name = name.split(".")
+        name = name[0]+'-'+name[1]
         name = name.replace("_", "-")
         appname = ''
         try:
@@ -454,7 +499,7 @@ def destroy(self, name):
         status = resp.status
         data = resp.read()
         con_serv.close()
-        if not 200 <= status <= 299:
+        if status != 404 and not 200 <= status <= 299:
             errmsg = "Failed to delete service:{} {} {} - {}".format(
                 name, status, reason, data)
             raise RuntimeError(errmsg)
@@ -529,7 +574,7 @@ def _pod_log(self, name):
         return (status, data, reason)
 
     def logs(self, name):
-        name = name.split(".")[0]
+        name = name.replace(".", "-")
         name = name.replace("_", "-")
         status, data, reason = self._get_pods()
         parsed_json = json.loads(data)
@@ -544,7 +589,7 @@ def run(self, name, image, entrypoint, command):
         """
         Run a one-off command
         """
-        name = name.split(".")[0]
+        name = name.replace(".", "-")
         name = name.replace("_", "-")
         l = {}
         l["id"] = name
@@ -603,7 +648,8 @@ def run(self, name, image, entrypoint, command):
 
     def _get_pod_state(self, name):
         try:
-            name = name.split(".")[0]
+            name = name.split(".")
+            name = name[0]+'-'+name[1]
             name = name.replace("_", "-")
             for _ in xrange(120):
                 status, data, reason = self._get_pods()