Sree Kuchibhotla
9 years ago
parent
d67b35635e
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#!/usr/bin/env python2.7 |
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# Copyright 2015, Google Inc. |
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# All rights reserved. |
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# |
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# Redistribution and use in source and binary forms, with or without |
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# modification, are permitted provided that the following conditions are |
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# met: |
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# |
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# * Redistributions of source code must retain the above copyright |
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# notice, this list of conditions and the following disclaimer. |
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# * Redistributions in binary form must reproduce the above |
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# copyright notice, this list of conditions and the following disclaimer |
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# in the documentation and/or other materials provided with the |
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# distribution. |
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# * Neither the name of Google Inc. nor the names of its |
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# contributors may be used to endorse or promote products derived from |
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# this software without specific prior written permission. |
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# |
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
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# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
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# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
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# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
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# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
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# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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|
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import requests |
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import json |
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|
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REQUEST_TIMEOUT_SECS = 10 |
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|
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def make_pod_config(pod_name, image_name, container_port_list, cmd_list, |
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arg_list): |
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"""Creates a string containing the Pod defintion as required by the Kubernetes API""" |
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body = { |
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'kind': 'Pod', |
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'apiVersion': 'v1', |
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'metadata': { |
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'name': pod_name, |
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'labels': {'name': pod_name} |
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}, |
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'spec': { |
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'containers': [ |
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{ |
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'name': pod_name, |
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'image': image_name, |
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'ports': [] |
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} |
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] |
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} |
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} |
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# Populate the 'ports' list |
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for port in container_port_list: |
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port_entry = {'containerPort': port, 'protocol': 'TCP'} |
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body['spec']['containers'][0]['ports'].append(port_entry) |
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|
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# Add the 'Command' and 'Args' attributes if they are passed. |
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# Note: |
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# - 'Command' overrides the ENTRYPOINT in the Docker Image |
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# - 'Args' override the COMMAND in Docker image (yes, it is confusing!) |
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if len(cmd_list) > 0: |
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body['spec']['containers'][0]['command'] = cmd_list |
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if len(arg_list) > 0: |
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body['spec']['containers'][0]['args'] = arg_list |
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return json.dumps(body) |
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|
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|
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def make_service_config(service_name, pod_name, service_port_list, |
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container_port_list, is_headless): |
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"""Creates a string containing the Service definition as required by the Kubernetes API. |
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|
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NOTE: |
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This creates either a Headless* Service or 'LoadBalancer' service depending on |
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the is_headless parameter. For Headless services, there is no 'type' attribute |
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and the 'clusterIP' attribute is set to 'None'. Also, if the service is |
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Headless, Kubernetes creates DNS entries for Pods - i.e creates DNS A-records |
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mapping the service's name to the Pods' IPs |
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""" |
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if len(container_port_list) != len(service_port_list): |
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print( |
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'ERROR: container_port_list and service_port_list must be of same size') |
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return '' |
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body = { |
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'kind': 'Service', |
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'apiVersion': 'v1', |
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'metadata': { |
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'name': service_name, |
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'labels': { |
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'name': service_name |
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} |
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}, |
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'spec': { |
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'ports': [], |
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'selector': { |
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'name': pod_name |
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} |
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} |
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} |
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# Populate the 'ports' list in the 'spec' section. This maps service ports |
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# (port numbers that are exposed by Kubernetes) to container ports (i.e port |
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# numbers that are exposed by your Docker image) |
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for idx in range(len(container_port_list)): |
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port_entry = { |
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'port': service_port_list[idx], |
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'targetPort': container_port_list[idx], |
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'protocol': 'TCP' |
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} |
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body['spec']['ports'].append(port_entry) |
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|
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# Make this either a LoadBalancer service or a headless service depending on |
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# the is_headless parameter |
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if is_headless: |
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body['spec']['clusterIP'] = 'None' |
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else: |
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body['spec']['type'] = 'LoadBalancer' |
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return json.dumps(body) |
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|
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|
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def print_connection_error(msg): |
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print('ERROR: Connection failed. Did you remember to run Kubenetes proxy on' |
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'localhost (i.e kubectl proxy --port=<proxy_port>) ?. Error: %s' % msg) |
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|
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def do_post(post_url, api_name, request_body): |
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"""Helper to do HTTP POST. |
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|
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Note: |
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1) On success, Kubernetes returns a success code of 201(CREATED) not 200(OK) |
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2) A response code of 509(CONFLICT) is interpreted as a success code (since |
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the error is most likely due to the resource already existing). This makes |
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do_pos() idempotent which is semantically desirable. |
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""" |
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is_success = True |
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try: |
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r = requests.post(post_url, data=request_body, timeout=REQUEST_TIMEOUT_SECS) |
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if r.status_code == requests.codes.conflict: |
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print('WARN: Looks like the resource already exists. Api: %s, url: %s' % |
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(api_name, post_url)) |
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elif r.status_code != requests.codes.created and r.status_code != requests.codes.ok: |
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print('ERROR: %s API returned error. HTTP response: %s' % |
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(api_name, r.text)) |
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is_success = False |
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except(requests.exceptions.Timeout, requests.exceptions.ConnectionError) as e: |
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is_success = False |
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print_connection_error(str(e)) |
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return is_success |
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|
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def do_delete(del_url, api_name): |
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"""Helper to do HTTP DELETE. |
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|
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Note: A response code of 404(NOT_FOUND) is treated as success to keep |
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do_delete() idempotent. |
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""" |
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is_success = True |
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try: |
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r = requests.delete(del_url, timeout=REQUEST_TIMEOUT_SECS) |
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if r.status_code == requests.codes.not_found: |
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print('WARN: The resource does not exist. Api: %s, url: %s' % |
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(api_name, del_url)) |
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elif r.status_code != requests.codes.ok: |
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print('ERROR: %s API returned error. HTTP response: %s' % |
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(api_name, r.text)) |
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is_success = False |
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except(requests.exceptions.Timeout, requests.exceptions.ConnectionError) as e: |
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is_success = False |
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print_connection_error(str(e)) |
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return is_success |
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|
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|
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def create_service(kube_host, kube_port, namespace, service_name, pod_name, |
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service_port_list, container_port_list, is_headless): |
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"""Creates a either a Headless Service or a LoadBalancer Service depending |
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on the is_headless parameter. |
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""" |
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post_url = 'http://%s:%d/api/v1/namespaces/%s/services' % ( |
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kube_host, kube_port, namespace) |
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request_body = make_service_config(service_name, pod_name, service_port_list, |
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container_port_list, is_headless) |
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return do_post(post_url, 'Create Service', request_body) |
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|
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|
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def create_pod(kube_host, kube_port, namespace, pod_name, image_name, |
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container_port_list, cmd_list, arg_list): |
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"""Creates a Kubernetes Pod. |
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|
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Note that it is generally NOT considered a good practice to directly create |
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Pods. Typically, the recommendation is to create 'Controllers' to create and |
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manage Pods' lifecycle. Currently Kubernetes only supports 'Replication |
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Controller' which creates a configurable number of 'identical Replicas' of |
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Pods and automatically restarts any Pods in case of failures (for eg: Machine |
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failures in Kubernetes). This makes it less flexible for our test use cases |
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where we might want to slightly different set of args to each Pod and hence we |
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directly create Pods (and not care much about Kubernetes failures since those |
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are very rare). |
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""" |
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post_url = 'http://%s:%d/api/v1/namespaces/%s/pods' % (kube_host, kube_port, |
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namespace) |
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request_body = make_pod_config(pod_name, image_name, container_port_list, |
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cmd_list, arg_list) |
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return do_post(post_url, 'Create Pod', request_body) |
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|
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def delete_service(kube_host, kube_port, namespace, service_name): |
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del_url = 'http://%s:%d/api/v1/namespaces/%s/services/%s' % ( |
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kube_host, kube_port, namespace, service_name) |
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return do_delete(del_url, 'Delete Service') |
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|
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def delete_pod(kube_host, kube_port, namespace, pod_name): |
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del_url = 'http://%s:%d/api/v1/namespaces/%s/pods/%s' % (kube_host, kube_port, |
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namespace, pod_name) |
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return do_delete(del_url, 'Delete Pod') |
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