This post will cover Rackspace On Metal, an intro to Docker, review of CoreOS & Fleet and demonstrate how one could use all of them to build a multi-tier application.
The associated presentation on this can be found at http://bit.ly/rs-onmetal-docker & the code at https://github.com/srirajan/onmetal-docker
Before you start
You will need the following- A Rackspace cloud account. Get a free tier Rackspace developer account - https://developer.rackspace.com/signup/
- If you don't have an account, you can still follow this and do it on your own servers. Some of the examples are specific to Rackspace cloud servers but the ones around Docker, CoreOS and Fleet can be done on any server.
- Ensure you have novaclient installed. Refer to http://www.rackspace.com/knowledge_center/article/installing-python-novaclient-on-linux-and-mac-os for more details.
Rackspace On Metal
Onmetal provides single-tenant bare metal servers and you read more about it here
http://www.rackspace.com/cloud/servers/onmetalAs of Dec, 2014, On Metal is only available in US region of IAD. So you need a Rackspace US cloud account.
We will have two groups of servers.
- First we will build a single Ubuntu 14.04 LTS (Trusty Tahr) On Metal server
key=sri-mb nova boot --flavor onmetal-compute1 \ --image 6cbfd76c-644c-4e28-b3bf-5a6c2a879a4a \ --key-name $key \ --poll play01
- Now prepare CoreOS cluster. First get a discovery URL for your cluster. More on this at https://coreos.com/docs/cluster-management/setup/cluster-discovery/
curl -w "\n" https://discovery.etcd.io/new
- Edit the cloud init file named coreos-cluster/cloudinit.yaml. Replace the token url from above.
- If you are doing on On Metal use coreos-cluster/cloudinit-onmetal.yaml as a workaround for https://github.com/coreos/coreos-cloudinit/issues/195. Eventually the above should work on both flavors.
- Decide which flavor you are using
#On metal flavor=onmetal-compute1 image=75a86b9d-e016-4cb7-8532-9e9b9b5fc58b key=sri-mb cloudinit=cloudinit-onmetal.yaml # Performance flavor=performance1-1 image=749dc22a-9563-4628-b0d1-f84ced8c7b7a key=sri-mb cloudinit=cloudinit.yaml
- Boot 4 servers for the cluster
nova boot --flavor $flavor --image $image --key-name $key \ --config-drive true --user-data $cloudinit core01 nova boot --flavor $flavor --image $image --key-name $key \ --config-drive true --user-data $cloudinit core02 nova boot --flavor $flavor --image $image --key-name $key \ --config-drive true --user-data $cloudinit core03 nova boot --flavor $flavor --image $image --key-name $key \ --config-drive true --user-data $cloudinit core04
Docker
Now let's play a litte with Docker.- Install docker on Ubuntu (play01 above)
apt-get update apt-get install -y docker.io screen git vim update-rc.d docker.io defaults
- Pull our first image. Review the listing & you should have 3 centos images for each of the versions.
docker pull centos docker images
- Run it. '-i' is for interactive & '-t' allocates a pseudo-tty.
docker run -i -t centos /bin/bash
- This runs the default image for CentOS. Review the inside to see how this looks inside docker.
cat /etc/redhat-release ps ls whoami cat /etc/hosts exit
- List Docker processes
docker ps -a
- Run a different release
docker run -i -t centos:centos6 /bin/bash cat /etc/redhat-release exit
- On the host (play01) with the networking. Docker uses a combination of Linux bridges and iptables to build managed networking on the container, communication with other containers and communication from the outside.
ifconfig docker0 iptables -nvL iptables -nvL -t nat
- Let's run something more than bash.
docker run -d centos python -m SimpleHTTPServer 8888
- And check a few things.
docker ps docker top <container UID> docker inspect <container UID> |less curl http://<container IP>:8888
- Let's do some more. Clone the repo from git
apt-get install -y git git clone https://github.com/srirajan/onmetal-docker
- Review the Dockerfile. This image file installs Nginx and PHP & loads a sample php file
cd /root/onmetal-docker/ubuntu_phpapp cat Dockerfile docker build -t="srirajan/ubuntu_phpapp" . docker images
- Run the container and map the port 80 on the container to port 8082 on the host. You can curl the URL to see the site.
docker run -d -p 8082:80 "srirajan/ubuntu_phpapp" docker top <container UID> docker logs <container UID> docker inspect <container UID> #curl the container IP curl http://<container IP>/home.php #curl the public IP and port curl http://<IP>:8082/home.php
- Docker diff
docker diff <container UID>
- Now let's look at linking containers. Start a mysql container and map the mysql port on the container to the host port 3306
docker run --name db -e MYSQL_ROOT_PASSWORD=dh47dk504dk44dd -d -p 3306:3306 mysql docker logs db
- Build the helper container
cd /root/onmetal-docker/dbhelper docker build -t="srirajan/dbhelper" .
- Start a helper container as a linked container and check it's environment variables. Linking allows information to be shared across containers. You can read more about linking here https://docs.docker.com/userguide/dockerlinks/
docker run --name dbhelper --link db:db srirajan/dbhelper env
- Now if you run the actual container as it is, it will login to the mysql instance on the db container and install the world database.
docker rm dbhelper docker run -d --name dbhelper --link db:db srirajan/dbhelper /usr/local/bin/configuredb.sh docker logs dbhelper
CoreOS, Fleet & Docker
- In the above steps, we should have created 4 core os machines with cloudinit. Now, lets play with CoreOS, etcd and Fleet. This should list all 4 machines in the cluster. Fleet is a distributed cluster management tool. It relies on etcd, which is a distributed key value store for operation. It also works with systemd files and behaves like a distributed systemd in a multi-node setup.
fleetctl list-machines
- Pull our repo on one of the nodes.
git clone https://github.com/srirajan/onmetal-docker
- Review and load all the services. We will go into details of each service in following steps.
cd /home/core/onmetal-docker/fleet-services fleetctl submit *.service
fleetctl list-unit-files UNIT HASH DSTATE STATE TARGET db.service fbf415a launched launched - dbhelper.service 747c778 inactive inactive - lbhelper.service 0592528 inactive inactive - mondb.service a4f50cc inactive inactive - monweb@.service d5ed242 inactive inactive - web@.service 0ac8be5 inactive inactive -
- Run the db service.
fleetctl start db.service Unit db.service launched on 2aa4e35a.../10.208.201.253 fleetctl list-units UNIT MACHINE ACTIVE SUB db.service 2aa4e35a.../10.208.201.253 active running
- You can also review the systemd service file. This one is fairly simple service and runs a mysql container on one of the hosts. Wait for this service to start before proceeding. Also note, that Fleet decides which host to run the container on.
cat db.service
[Unit]
Description=DB service
Requires=etcd.service
[Service]
EnvironmentFile=/etc/environment
TimeoutStartSec=0
ExecStartPre=/usr/bin/docker pull mysql
ExecStart=/usr/bin/docker run --rm --name db -e MYSQL_ROOT_PASSWORD=dh47dk504dk44dd -p ${COREOS_PRIVATE_IPV4}:3306:3306 mysql
ExecStop=/usr/bin/docker stop db
Restart=always
- One oddity with fleet is that to query the status, you have to run the command on the host running the container.
fleetctl status db.service db.service - DB service Loaded: loaded (/run/fleet/units/db.service; linked-runtime) Active: active (running) since Thu 2014-11-13 14:11:06 UTC; 8min ago Process: 22050 ExecStartPre=/usr/bin/docker pull mysql (code=exited, status=0/SUCCESS) Main PID: 22068 (docker) CGroup: /system.slice/db.service └─22068 /usr/bin/docker run --rm --name db -e MYSQL_ROOT_PASSWORD=dh47dk504dk44dd -p 10.208.201.253:3306:3306 mysql Nov 13 14:11:12 core04 docker[22068]: 2014-11-13 14:11:12 1 [Warning] No existing UUID has been found, so we assume that this is the first time that this server has been started. Generating a new UUID: ec53a4d8-6b3e-11e4-8386-0a1bbbebe238. Nov 13 14:11:12 core04 docker[22068]: 2014-11-13 14:11:12 1 [Note] Server hostname (bind-address): '*'; port: 3306 Nov 13 14:11:12 core04 docker[22068]: 2014-11-13 14:11:12 1 [Note] IPv6 is available. Nov 13 14:11:12 core04 docker[22068]: 2014-11-13 14:11:12 1 [Note] - '::' resolves to '::'; Nov 13 14:11:12 core04 docker[22068]: 2014-11-13 14:11:12 1 [Note] Server socket created on IP: '::'. Nov 13 14:11:12 core04 docker[22068]: 2014-11-13 14:11:12 1 [Note] Event Scheduler: Loaded 0 events Nov 13 14:11:12 core04 docker[22068]: 2014-11-13 14:11:12 1 [Note] Execution of init_file '/tmp/mysql-first-time.sql' started. Nov 13 14:11:12 core04 docker[22068]: 2014-11-13 14:11:12 1 [Note] Execution of init_file '/tmp/mysql-first-time.sql' ended. Nov 13 14:11:12 core04 docker[22068]: 2014-11-13 14:11:12 1 [Note] mysqld: ready for connections. Nov 13 14:11:12 core04 docker[22068]: Version: '5.6.21' socket: '/tmp/mysql.sock' port: 3306 MySQL Community Server (GPL)
- dbhelper.service uses container linking to install the mysql world database and configure some users for our application. The systemd configuration tells fleet to run on the same host as the db.service. mondb.service is not a container but uses systemd to run a script that updates etcd with the information about the db service. In this case we are just pushing private IPs to etcd but this can be leveraged to do other things as well.
fleetctl start dbhelper.service Unit dbhelper.service launched on 2aa4e35a.../10.208.201.253 fleetctl start mondb.service Unit mondb.service launched on 2aa4e35a.../10.208.201.253
- Run fleetctl again to see where our containers are deployed. Because of our systemd definition file, fleet will ensure they run on the same host.
fleetctl list-units UNIT MACHINE ACTIVE SUB db.service 2aa4e35a.../10.208.201.253 active running dbhelper.service 2aa4e35a.../10.208.201.253 active running mondb.service 2aa4e35a.../10.208.201.253 active running
- You can also login to the host running the dbhelper service and review the journal (logs) for the service.
fleetctl journal dbhelper -- Logs begin at Mon 2014-11-10 21:00:41 UTC, end at Thu 2014-11-13 14:23:43 UTC. -- Nov 11 05:22:51 core04.novalocal systemd[1]: Stopped DB Helperservice. Nov 11 05:22:51 core04.novalocal systemd[1]: Unit dbhelper.service entered failed state. -- Reboot -- Nov 13 14:22:43 core04 systemd[1]: Starting DB Helperservice... Nov 13 14:22:43 core04 docker[22239]: Pulling repository srirajan/dbhelper Nov 13 14:23:00 core04 systemd[1]: Started DB Helperservice. Nov 13 14:23:06 core04 docker[22272]: Creating the world database Nov 13 14:23:13 core04 docker[22272]: Creating application user Nov 13 14:23:13 core04 docker[22272]: Counting rows in world.city Nov 13 14:23:13 core04 docker[22272]: COUNT(*) Nov 13 14:23:13 core04 docker[22272]: 4079
- Now let's move on the web containers. Start the one container from the web service. In systemd a service with @ is generic service and you can append values to start as many of them. The first container will take a little bit of time as it is downloading the container.
fleetctl start web@01.service Unit web@01.service launched on 6847f4f7.../10.208.201.226 fleetctl list-units UNIT MACHINE ACTIVE SUB db.service 2aa4e35a.../10.208.201.253 active running dbhelper.service 2aa4e35a.../10.208.201.253 active running mondb.service 2aa4e35a.../10.208.201.253 active running web@01.service 6847f4f7.../10.208.201.226 active running
- Start 9 more web containers. Fleet will disribute them across the different hosts.
fleetctl start web@{02..10}.service
Unit web@04.service launched on ee5398cf.../10.208.201.250
Unit web@10.service launched on 2aa4e35a.../10.208.201.253
Unit web@07.service launched on 6847f4f7.../10.208.201.226
Unit web@09.service launched on ee5398cf.../10.208.201.250
Unit web@03.service launched on 6847f4f7.../10.208.201.226
Unit web@05.service launched on c3f52cb3.../10.208.201.234
Unit web@02.service launched on ee5398cf.../10.208.201.250
Unit web@06.service launched on c3f52cb3.../10.208.201.234
Unit web@08.service launched on c3f52cb3.../10.208.201.234
fleetctl list-units
UNIT MACHINE ACTIVE SUB
db.service 2aa4e35a.../10.208.201.253 active running
dbhelper.service 2aa4e35a.../10.208.201.253 active running
mondb.service 2aa4e35a.../10.208.201.253 active running
web@01.service 6847f4f7.../10.208.201.226 active running
web@02.service ee5398cf.../10.208.201.250 active running
web@03.service 6847f4f7.../10.208.201.226 active running
web@04.service ee5398cf.../10.208.201.250 active running
web@05.service c3f52cb3.../10.208.201.234 active running
web@06.service c3f52cb3.../10.208.201.234 active running
web@07.service 6847f4f7.../10.208.201.226 active running
web@08.service c3f52cb3.../10.208.201.234 active running
web@09.service ee5398cf.../10.208.201.250 active running
web@10.service 2aa4e35a.../10.208.201.253 active running
- Start the monweb services. These are similar to the mondb.service and update etcd with different values from the running containers.
fleetctl start monweb@{01..10}.service
Unit monweb@04.service launched on ee5398cf.../10.208.201.250
Unit monweb@02.service launched on ee5398cf.../10.208.201.250
Unit monweb@01.service launched on 6847f4f7.../10.208.201.226
Unit monweb@05.service launched on c3f52cb3.../10.208.201.234
Unit monweb@03.service launched on 6847f4f7.../10.208.201.226
Unit monweb@09.service launched on ee5398cf.../10.208.201.250
Unit monweb@07.service launched on 6847f4f7.../10.208.201.226
Unit monweb@10.service launched on 2aa4e35a.../10.208.201.253
Unit monweb@08.service launched on c3f52cb3.../10.208.201.234
Unit monweb@06.service launched on c3f52cb3.../10.208.201.234
fleetctl list-units
UNIT MACHINE ACTIVE SUB
db.service 2aa4e35a.../10.208.201.253 active running
dbhelper.service 2aa4e35a.../10.208.201.253 active running
mondb.service 2aa4e35a.../10.208.201.253 active running
monweb@01.service 6847f4f7.../10.208.201.226 active running
monweb@02.service ee5398cf.../10.208.201.250 active running
monweb@03.service 6847f4f7.../10.208.201.226 active running
monweb@04.service ee5398cf.../10.208.201.250 active running
monweb@05.service c3f52cb3.../10.208.201.234 active running
monweb@06.service c3f52cb3.../10.208.201.234 active running
monweb@07.service 6847f4f7.../10.208.201.226 active running
monweb@08.service c3f52cb3.../10.208.201.234 active running
monweb@09.service ee5398cf.../10.208.201.250 active running
monweb@10.service 2aa4e35a.../10.208.201.253 active running
web@01.service 6847f4f7.../10.208.201.226 active running
web@02.service ee5398cf.../10.208.201.250 active running
web@03.service 6847f4f7.../10.208.201.226 active running
web@04.service ee5398cf.../10.208.201.250 active running
web@05.service c3f52cb3.../10.208.201.234 active running
web@06.service c3f52cb3.../10.208.201.234 active running
web@07.service 6847f4f7.../10.208.201.226 active running
web@08.service c3f52cb3.../10.208.201.234 active running
web@09.service ee5398cf.../10.208.201.250 active running
web@10.service 2aa4e35a.../10.208.201.253 active running
- Query etcd for values. This will return the IP addresses and ports of the web containers.
for i in {01..10}; do etcdctl get /services/web/web$i/unit; etcdctl get /services/web/web$i/host; etcdctl get /services/web/web$i/public_ipv4_addr; etcdctl get /services/web/web$i/port; echo "-----" ; done
monweb@01.service
core01
162.242.254.113
18001
-----
monweb@02.service
core03
162.242.255.71
18002
-----
monweb@03.service
core01
162.242.254.113
18003
-----
monweb@04.service
core03
162.242.255.71
18004
-----
monweb@05.service
core02
162.242.254.215
18005
-----
monweb@06.service
core02
162.242.254.215
18006
-----
monweb@07.service
core01
162.242.254.113
18007
-----
monweb@08.service
core02
162.242.254.215
18008
-----
monweb@09.service
core03
162.242.255.71
18009
-----
monweb@10.service
core04
162.242.255.73
18010
-----
- Test the site on one of the container.
curl http://162.242.255.73:18010/home.php <!DOCTYPE html> <html> <body> <strong>There is no place like 127.0.0.1</strong><br/>Date & Time: 2014-11-13 14:29:18<br/>Container name: dca363b9af75<hr/> </body> </html>
- At this point, we have database container running and a bunch of web containers running on different hosts. The communication between them has been established as well.
- Optionally, we can run the lbhelper service that updates the cloud load balancer. This requires a Rackspace cloud load balancer pre-configured and you need to set the values in etcd
etcdctl set /services/rscloud/OS_USERNAME <cloud username> etcdctl set /services/rscloud/OS_REGION <cloud region> etcdctl set /services/rscloud/OS_PASSWORD <cloud api key> etcdctl set /services/rscloud/OS_TENANT_NAME <cloud account no> etcdctl set /services/rscloud/LB_NAME <cloud lb name> etcdctl set /services/rscloud/SERVER_HEALTH_URL health.php etcdctl set /services/rscloud/SERVER_HEALTH_DIGEST dbe72348d4e3aa87958f421e4a9592a82839f3d8 </ODE>
- Now run the lbhelper service.
fleetctl start lbhelper.service Unit lbhelper.service launched on 2aa4e35a.../10.208.201.253 fleetctl list-units UNIT MACHINE ACTIVE SUB db.service 2aa4e35a.../10.208.201.253 active running dbhelper.service 2aa4e35a.../10.208.201.253 active running lbhelper.service 2aa4e35a.../10.208.201.253 active running mondb.service 2aa4e35a.../10.208.201.253 active running monweb@01.service 6847f4f7.../10.208.201.226 active running monweb@02.service ee5398cf.../10.208.201.250 active running monweb@03.service 6847f4f7.../10.208.201.226 active running monweb@04.service ee5398cf.../10.208.201.250 active running monweb@05.service c3f52cb3.../10.208.201.234 active running monweb@06.service c3f52cb3.../10.208.201.234 active running monweb@07.service 6847f4f7.../10.208.201.226 active running monweb@08.service c3f52cb3.../10.208.201.234 active running monweb@09.service ee5398cf.../10.208.201.250 active running monweb@10.service 2aa4e35a.../10.208.201.253 active running web@01.service 6847f4f7.../10.208.201.226 active running web@02.service ee5398cf.../10.208.201.250 active running web@03.service 6847f4f7.../10.208.201.226 active running web@04.service ee5398cf.../10.208.201.250 active running web@05.service c3f52cb3.../10.208.201.234 active running web@06.service c3f52cb3.../10.208.201.234 active running web@07.service 6847f4f7.../10.208.201.226 active running web@08.service c3f52cb3.../10.208.201.234 active running web@09.service ee5398cf.../10.208.201.250 active running web@10.service 2aa4e35a.../10.208.201.253 active running
- You can look at the logs from it. This container runs a python script that will populate the load balancer with the IP addresses and port numbers from the web containers. The script queries etcd for the information and also does a health check to determine the status of the container.
docker logs lbhelper [11/13/14 14:35:48][INFO]:Authenticated using rtsdemo10 [11/13/14 14:36:32][INFO]:web 01 Found. Processing server [11/13/14 14:36:32][INFO]:Health test passed. Adding to load balancer [11/13/14 14:36:32][INFO]:Load balancer pool myworld found [11/13/14 14:36:32][INFO]:Adding server to load balancer [11/13/14 14:36:33][INFO]:web 02 Found. Processing server [11/13/14 14:36:33][INFO]:Health test passed. Adding to load balancer [11/13/14 14:36:33][INFO]:Load balancer pool myworld found [11/13/14 14:36:33][INFO]:Adding server to load balancer [11/13/14 14:36:44][INFO]:web 03 Found. Processing server [11/13/14 14:36:44][INFO]:Health test passed. Adding to load balancer [11/13/14 14:36:44][INFO]:Load balancer pool myworld found [11/13/14 14:36:44][INFO]:Adding server to load balancer [11/13/14 14:36:55][INFO]:web 04 Found. Processing server [11/13/14 14:36:55][INFO]:Health test passed. Adding to load balancer [11/13/14 14:36:55][INFO]:Load balancer pool myworld found [11/13/14 14:36:55][INFO]:Adding server to load balancer [11/13/14 14:37:06][INFO]:web 05 Found. Processing server [11/13/14 14:37:06][INFO]:Health test passed. Adding to load balancer [11/13/14 14:37:06][INFO]:Load balancer pool myworld found [11/13/14 14:37:06][INFO]:Adding server to load balancer [11/13/14 14:37:12][INFO]:web 06 Found. Processing server [11/13/14 14:37:12][INFO]:Health test passed. Adding to load balancer [11/13/14 14:37:12][INFO]:Load balancer pool myworld found [11/13/14 14:37:13][INFO]:Adding server to load balancer [11/13/14 14:37:23][INFO]:web 07 Found. Processing server [11/13/14 14:37:23][INFO]:Health test passed. Adding to load balancer [11/13/14 14:37:23][INFO]:Load balancer pool myworld found [11/13/14 14:37:24][INFO]:Adding server to load balancer [11/13/14 14:37:34][INFO]:web 08 Found. Processing server [11/13/14 14:37:34][INFO]:Health test passed. Adding to load balancer [11/13/14 14:37:34][INFO]:Load balancer pool myworld found [11/13/14 14:37:35][INFO]:Adding server to load balancer [11/13/14 14:37:45][INFO]:web 09 Found. Processing server [11/13/14 14:37:45][INFO]:Health test passed. Adding to load balancer [11/13/14 14:37:46][INFO]:Load balancer pool myworld found [11/13/14 14:37:46][INFO]:Adding server to load balancer [11/13/14 14:37:57][INFO]:web 10 Found. Processing server [11/13/14 14:37:57][INFO]:Health test passed. Adding to load balancer [11/13/14 14:37:57][INFO]:Load balancer pool myworld found [11/13/14 14:37:57][INFO]:Adding server to load balancer [11/13/14 14:38:08][INFO]:web 11 does not exist.Skipping... [11/13/14 14:38:08][INFO]:web 12 does not exist.Skipping... [11/13/14 14:38:08][INFO]:web 13 does not exist.Skipping... [11/13/14 14:38:08][INFO]:web 14 does not exist.Skipping... [11/13/14 14:38:08][INFO]:web 28 does not exist.Skipping... [11/13/14 14:38:08][INFO]:web 29 does not exist.Skipping... [11/13/14 14:38:08][INFO]:web 30 does not exist.Skipping... [11/13/14 14:38:08][INFO]:web 31 does not exist.Skipping... [11/13/14 14:38:08][INFO]:web 32 does not exist.Skipping... [11/13/14 14:38:08][INFO]:web 33 does not exist.Skipping... [11/13/14 14:38:08][INFO]:web 60 does not exist.Skipping... <truncated> [11/13/14 14:38:08][INFO]:web 97 does not exist.Skipping... [11/13/14 14:38:08][INFO]:web 98 does not exist.Skipping... [11/13/14 14:38:08][INFO]:web 99 does not exist.Skipping... [11/13/14 14:38:08][INFO]:Printing summary [11/13/14 14:38:08][INFO]:Load balancer pool myworld found [11/13/14 14:38:08][INFO]:Nodes: 1.1.1.1 80 [11/13/14 14:38:08][INFO]:Nodes: 162.242.254.113 18001 [11/13/14 14:38:08][INFO]:Nodes: 162.242.255.71 18002 [11/13/14 14:38:08][INFO]:Nodes: 162.242.254.113 18003 [11/13/14 14:38:08][INFO]:Nodes: 162.242.255.71 18004 [11/13/14 14:38:08][INFO]:Nodes: 162.242.254.215 18005 [11/13/14 14:38:08][INFO]:Nodes: 162.242.254.215 18006 [11/13/14 14:38:08][INFO]:Nodes: 162.242.254.113 18007 [11/13/14 14:38:08][INFO]:Nodes: 162.242.254.215 18008 [11/13/14 14:38:08][INFO]:Nodes: 162.242.255.71 18009 [11/13/14 14:38:08][INFO]:Nodes: 162.242.255.73 18010 [11/13/14 14:38:08][INFO]:Sleeping 10 seconds...
- This covers our initial exploration of Docker, CoreOS and Fleet. There is more these tools can do to help with tighter integration but overall this combination is a good way to manage docker containers and run serious workloads on it.
Misc Commands
A collection of random snippets that are useful.- Build without cache. This burnt me the first time. Ubuntu removes old package versions from their repos and if a cached image has that version, apt-get install will try to pull that and fail. Needless to say --no-cache will takelonger to build.
docker build --no-cache
- Review logs of etcd and fleet
journalctl -u etcd journalctl -u fleet
- Delete all containers
docker stop $(docker ps -a -q) sleep 2 docker rm $(docker ps -a -q)
- Delete all images
docker rmi $(docker images -q)
- Cleanup fleet
fleetctl destroy $(fleetctl list-units -fields=unit -no-legend) fleetctl destroy $(fleetctl list-unit-files -fields=unit -no-legend) sleep 5 fleetctl list-unit-files fleetctl list-units
- Restart Fleet
sudo systemctl restart fleet.service
Resources
- Free Rackspace developer account - https://developer.rackspace.com/signup/
- Core OS - https://coreos.com/docs/
- A good overview on why docker was created. Done by dotCloud founder and CTO Solomon Hykes - https://www.youtube.com/watch?v=Q5POuMHxW-0 -
- Getting Started with systemd - https://coreos.com/docs/launching-containers/launching/getting-started-with-systemd/
