added docker service file from r603
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daemon/core/services/dockersvc.py
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daemon/core/services/dockersvc.py
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#
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# CORE
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# Copyright (c)2014 the Boeing Company.
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# See the LICENSE file included in this distribution.
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#
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# authors: Stuart Marsden
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# Jeff Ahrenholz <jeffrey.m.ahrenholz@boeing.com>
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#
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''' Docker service allows running docker containers within CORE nodes.
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The running of Docker within a CORE node allows for additional extensibility to
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the CORE services. This allows network applications and protocols to be easily
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packaged and run on any node.
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This service that will add a new group to the services list. This
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will have a service called Docker which will just start the docker service
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within the node but not run anything. It will also scan all docker images on
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the host machine. If any are tagged with 'core' then they will be added as a
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service to the Docker group. The image will then be auto run if that service is
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selected.
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This requires a recent version of Docker. This was tested using a PPA on Ubuntu
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with version 1.2.0. The version in the standard Ubuntu repo is to old for
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this purpose (we need --net host).
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It also requires docker-py (https://pypi.python.org/pypi/docker-py) which can be
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installed with 'pip install docker-py'. This is used to interface with Docker
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from the python service.
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An example use case is to pull an image from Docker.com. A test image has been
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uploaded for this purpose:
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sudo docker pull stuartmarsden/multicastping
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This downloads an image which is based on Ubuntu 14.04 with python and twisted.
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It runs a simple program that sends a multicast ping and listens and records
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any it receives.
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In order for this to appear as a docker service it must be tagged with core.
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Find out the id by running 'sudo docker images'. You should see all installed
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images and the one you want looks like this:
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stuartmarsden/multicastping latest 4833487e66d2 20 hours
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ago 487 MB
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The id will be different on your machine so use it in the following command:
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sudo docker tag 4833487e66d2 stuartmarsden/multicastping:core
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This image will be listed in the services after we restart the core-daemon:
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sudo service core-daemon restart
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You can set up a simple network with a number of PCs connected to a switch. Set
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the stuartmarsden/multicastping service for all the PCs. When started they will
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all begin sending Multicast pings.
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In order to see what is happening you can go in to the terminal of a node and
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look at the docker log. Easy shorthand is:
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docker logs $(docker ps -q)
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Which just shows the log of the running docker container (usually just one per
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node). I have added this as an observer node to my setup: Name: docker logs
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Command: bash -c 'docker logs $(docker ps -q) | tail -20'
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So I can just hover over to see the log which looks like this:
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Datagram 'Client: Ping' received from ('10.0.0.20', 8005)
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Datagram 'Client: Ping' received from ('10.0.5.21', 8005)
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Datagram 'Client: Ping' received from ('10.0.3.20', 8005)
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Datagram 'Client: Ping' received from ('10.0.4.20', 8005)
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Datagram 'Client: Ping' received from ('10.0.4.20', 8005)
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Datagram 'Client: Ping' received from ('10.0.1.21', 8005)
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Datagram 'Client: Ping' received from ('10.0.4.21', 8005)
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Datagram 'Client: Ping' received from ('10.0.4.21', 8005)
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Datagram 'Client: Ping' received from ('10.0.5.20', 8005)
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Datagram 'Client: Ping' received from ('10.0.0.21', 8005)
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Datagram 'Client: Ping' received from ('10.0.3.21', 8005)
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Datagram 'Client: Ping' received from ('10.0.0.20', 8005)
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Datagram 'Client: Ping' received from ('10.0.5.21', 8005)
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Datagram 'Client: Ping' received from ('10.0.3.20', 8005)
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Datagram 'Client: Ping' received from ('10.0.4.20', 8005)
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Datagram 'Client: Ping' received from ('10.0.4.20', 8005)
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Datagram 'Client: Ping' received from ('10.0.1.21', 8005)
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Datagram 'Client: Ping' received from ('10.0.4.21', 8005)
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Datagram 'Client: Ping' received from ('10.0.4.21', 8005)
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Datagram 'Client: Ping' received from ('10.0.5.20', 8005)
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Limitations:
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1. Docker images must be downloaded on the host as usually a CORE node does not
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have access to the internet.
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2. Each node isolates running containers (keeps things simple)
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3. Recent version of docker needed so that --net host can be used. This does
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not further abstract the network within a node and allows multicast which
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is not enabled within Docker containers at the moment.
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4. The core-daemon must be restarted for new images to show up.
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5. A Docker-daemon is run within each node but the images are shared. This
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does mean that the daemon attempts to access an SQLlite database within the
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host. At startup all the nodes will try to access this and it will be locked
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for most due to contention. The service just does a hackish wait for 1 second
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and retry. This means all the docker containers can take a while to come up
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depending on how many nodes you have.
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'''
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import os
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import sys
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try:
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from docker import Client
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except Exception:
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pass
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from core.service import CoreService, addservice
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from core.misc.ipaddr import IPv4Prefix, IPv6Prefix
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class DockerService(CoreService):
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''' This is a service which will allow running docker containers in a CORE
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node.
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'''
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_name = "Docker"
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_group = "Docker"
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_depends = ()
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_dirs = ('/var/lib/docker/containers/', '/run/shm', '/run/resolvconf',)
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_configs = ('docker.sh', )
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_startindex = 50
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_startup = ('sh docker.sh',)
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_shutdown = ('service docker stop', )
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# Container image to start
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_image = ""
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@classmethod
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def generateconfig(cls, node, filename, services):
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''' Returns a string having contents of a docker.sh script that
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can be modified to start a specific docker image.
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'''
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cfg = "#!/bin/sh\n"
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cfg += "# auto-generated by Docker (docker.py)\n"
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# Docker likes to think it has DNS set up or it complains.
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# Unless your network was attached to the Internet this is
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# non-functional but hides error messages.
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cfg += 'echo "nameserver 8.8.8.8" > /run/resolvconf/resolv.conf\n'
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# Starts the docker service. In Ubuntu this is docker.io; in other
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# distros may just be docker
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cfg += 'service docker start\n'
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cfg += "# you could add a command to start a image here eg:\n"
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if not cls._image:
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cfg += "# docker run -d --net host --name coreDock <imagename>\n"
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else:
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cfg += """\
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result=1
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until [ $result -eq 0 ]; do
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docker run -d --net host --name coreDock %s
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result=$?
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# this is to alleviate contention to docker's SQLite database
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sleep 0.3
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done
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""" % (cls._image, )
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return cfg
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addservice(DockerService)
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# This auto-loads Docker images having a :core tag, adding them to the list
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# of services under the "Docker" group.
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if 'Client' in globals():
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client = Client(version='1.10')
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images = client.images()
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del client
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else:
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images = []
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for image in images:
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if u'<none>' in image['RepoTags'][0]:
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continue
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for repo in image['RepoTags']:
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if u':core' not in repo:
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continue
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dockerid = repo.encode('ascii','ignore').split(':')[0]
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SubClass = type('SubClass', (DockerService,),
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{'_name': dockerid, '_image': dockerid})
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addservice(SubClass)
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del images
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