Docker+Consul

A whirlwind introduction to using Docker containers and their discovery with Consul.

Transcript

1. Generation X
4. everywhere is anywhere is anything is everything
5. Story Time
6. Docker+Consul by Justin Reagor
7. Justin Who? • Haydle employee #0 • 9 years of Ruby & Javascript • 20 (?) of Linux/UNIX • DevOp’er + Chef, front to back • Zero Java Experience (thanks Chariot!) • No year book anywhere holds my picture. True story.
9. Consul, Service Discovery and Docker
10. Assumptions • Some experience with Linux/UNIX (cmdline) • Edit plain text files • Install Linux distribution packages • Manage services/daemons • Basic networking, HTTP, and DNS • You know how to run your application
11. Follow Along • Install… • Docker v1.6.0 (Ubuntu) • Boot2Docker (OS X) • DigitalOcean’s Docker droplet • docker pull <images>
12. Containers are Containing
15. LXC • 5 years before Docker was started, Google, IBM, Parallels sponsored and introduced Linux Container support for the kernel. • Linux Containers, or LXC, provide the kernel with operating system level virtualization. • This allows the Linux Kernel to support multiple isolated user space instances, instead of just one. • LXC, along with many other technologies and interfaces, allowed Docker (the company) to build software (Docker Engine) to enhance the experience of using and deploying containerization.
16. "lightweight VMs"
17. "system-in-a-PID"
18. Docker Engine interfaces with the kernel • kernel level namespacing (namespace) • resource control groups (cgroups) • union file systems (UFS) • custom network bridge interface (docker0) • written in Go
20. Containers. Gone. Wild.
23. Docker Essentials • host server runs docker • docker daemon • docker command; executes commands on daemon • images built with Dockerfiles (plain text) • containers run from images • container ports bridge to host; other net options • containers can have tags & labels
24. Docker Essentials • docker commit new image from cont. changes • docker push/pull upload to an image registry • docker search search the registry • docker history list state changes of an image • docker port list NATed public-facing ports
25. $ docker run ubuntu:14.04 /bin/echo 'Hello world' Hello world
26. $ docker run -p 9200:9200 -p 9300:9300 elasticsearch
27. Dockerfile • Plain text • Used to create images • Execute a simple set of commands • Each execution creates a layer (think commits) • Images are made up of layers
28. FROM ubuntu:14.04 MAINTAINER Justin Reagor <jreagor@chariotsolutions.com> RUN apt-get -qq update RUN apt-get -qqy install build-essential ruby ruby-dev ADD . /home/www WORKDIR /home/www RUN echo 'gem: --no-rdoc --no-ri' >> /.gemrc RUN gem install bundler --no-ri --no-rdoc RUN gem install foreman --no-ri --no-rdoc RUN bundle install EXPOSE 5000 CMD ["foreman", "start"]
29. FROM gliderlabs/alpine:3.1 MAINTAINER Justin Reagor <justinwr@gmail.com> RUN apk --update add openssh zsh ca-certificates RUN ssh-keygen -t dsa -f /etc/ssh/ssh_host_dsa_key && ssh-keygen -t rsa -f /etc/ssh/ssh_host_rsa_key ONBUILD RUN mkdir -p /root/.ssh && chmod 700 /root/.ssh ONBUILD ADD root-id_rsa /root/.ssh/id_rsa ENV NOTVISIBLE "in users profile" RUN echo "export VISIBLE=now" >> /etc/profile EXPOSE 22 CMD ["/usr/sbin/sshd", "-D"]
30. $ docker build -t justinwr/dev .
31. $ docker run -d -p 2233:22 justinwr/dev
32. Demo?
33. Service = Discovery
35. Consul is a distributed, highly-available, and multi- datacenter aware tool for service discovery, configuration, and orchestration. In the ever- growing datacenter, Consul enables rapid deployment, configuration, and maintenance of service-oriented architectures.
38. Consul Essentials • Service Discovery • Distributed Key/Value Store • Failure Detection • Multi Datacenter
39. Consul Essentials • Also written in Go • Raft consensus algorithm for cluster elections • Query through DNS, REST, or RPC • Key/value store allows arbitrary data (think Chef Server) • Health checks allow behavior across cluster • Web UI!
40. Consul Essentials • Single agent • Runs as either server or client • Run at least 3 servers for a quorum • Stick a client agent in every container (why not?)
42. admin@hashicorp: curl -X PUT -d 'bar' http://localhost:8500/v1/kv/foo true admin@hashicorp: curl http://localhost:8500/v1/kv/foo [ { "CreateIndex": 100, "ModifyIndex": 200, "Key": "foo", "Flags": 0, "Value": "YmFy" } ]
43. Endpoints • kv - Key/Value store • agent - Consul Agent • catalog - Nodes and services • health - Health checks • session - Sessions • acl - Access Control Lists • event - User Events • status - Consul system status
44. admin@hashicorp: dig web-frontend.service.consul. ANY ; <<>> DiG 9.8.3-P1 <<>> web-frontend.service.consul. ANY ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 29981 ;; flags: qr aa rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 0 ;; QUESTION SECTION: ;web-frontend.service.consul. IN ANY ;; ANSWER SECTION: web-frontend.service.consul. 0 IN A 10.0.3.83 web-frontend.service.consul. 0 IN A 10.0.1.109
45. Now All The Things
46. # 'ubuntu' base image, tagged as version '14.04' FROM ubuntu:14.04 # author of this docker image MAINTAINER Justin Reagor <jreagor@chariotsolutions.com> # environment variable that tracks a version ENV REFRESHED_AT 2015-05-03 # update our base ubuntu image RUN apt-get -qqy update && apt-get -qqy install curl unzip # download and unpack Consul ADD https://dl.bintray.com/mitchellh/consul/0.5.0_linux_amd64.zip /tmp/consul.zip RUN cd /usr/sbin && unzip /tmp/consul.zip && chmod +x /usr/sbin/consul && rm /tmp/consul.zip # download and unpack Consul's web UI ADD https://dl.bintray.com/mitchellh/consul/0.5.0_web_ui.zip /tmp/webui.zip RUN cd /tmp/ && unzip webui.zip && mv dist/ /webui/ # add our configuration file ADD consul.json /config/ # expose some ports EXPOSE 53/udp 8300 8301 8301/udp 8302 8302/udp 8400 8500 # mount file system in our container VOLUME ["/data"] # makes these executable containers ENTRYPOINT [ "/usr/sbin/consul", "agent", "-config-dir=/config" ] # set additional defaults for ENTRYPOINT CMD []
47. $ docker build -t talk/consul .
48. $ docker pull progrium/consul
49. Consul Ports • Server RPC (Default 8300). This is used by servers to handle incoming requests from other agents. TCP only. • Serf LAN (Default 8301). This is used to handle gossip in the LAN. Required by all agents. TCP and UDP. • Serf WAN (Default 8302). This is used by servers to gossip over the WAN to other servers. TCP and UDP. • CLI RPC (Default 8400). This is used by all agents to handle RPC from the CLI. TCP only. • HTTP API (Default 8500). This is used by clients to talk to the HTTP API. TCP only. • DNS Interface (Default 8600). Used to resolve DNS queries. TCP and UDP.
50. $ CID="$(docker run —-rm -p 8400:8400 -p 8500:8500 -p 8600:53/udp -h node1 progrium/consul -server -bootstrap- expect 3 -ui-dir /ui)"
51. $ JOIN_IP="$(docker inspect -f '{{.NetworkSettings.IPAddress}}' $CID)"
52. $ for name in node{2,3}; do docker run —d --restart=no --name $name -h $name progrium/consul -server -join $JOIN_IP; done
53. $ docker run -d -P --restart=no --name agent1 -h agent1 progrium/consul -join $JOIN_IP
54. $ docker port agent1 53/udp -> 0.0.0.0:32769 8300/tcp -> 0.0.0.0:32772 8301/tcp -> 0.0.0.0:32768 8301/udp -> 0.0.0.0:32768 8302/tcp -> 0.0.0.0:32773 8400/tcp -> 0.0.0.0:32769 53/tcp -> 0.0.0.0:32770 8302/udp -> 0.0.0.0:32770 8500/tcp -> 0.0.0.0:32771
56. [tag.]<service>.service[.datacenter][.domain]
57. Demo?
58. Trick One Pony
59. consul-template • Generic template rendering and notifications with Consul • Loop and watch Consul for changes • Generate templates when it does • Execute scripts afterwards • Think chef-client but distributed and magical
60. $ consul-template \ -consul demo.consul.io \ -template "/tmp/template.ctmpl:/tmp/result"
61. $ consul-template \ -consul my.consul.internal:6124 \ -template "/tmp/nginx.ctmpl:/var/nginx/nginx.conf:service nginx restart" \ -template "/tmp/redis.ctmpl:/var/redis/redis.conf:service redis restart" \ -template "/tmp/haproxy.ctmpl:/var/haproxy/haproxy.conf"
62. global daemon maxconn {{key "service/haproxy/maxconn"}} defaults mode {{key "service/haproxy/mode"}}{{range ls "service/haproxy/timeouts"}} timeout {{.Key}} {{.Value}}{{end}} listen http-in bind *:8000{{range service "release.web"}} server {{.Node}} {{.Address}}:{{.Port}}{{end}}
63. Registrator • Watches for docker events • Automatically register/deregisters services for Docker containers • Create a container, automatically registered service • Works with Consul or it’s competitor etcd • Deadly with Consul’s DNS
64. $ docker run -d -h registrator1 \ -v /var/run/docker.sock:/tmp/docker.sock \ progrium/registrator consul://$JOIN_IP:8500
65. Services are registered and deregistered based on container start and die events from Docker. The service definitions are created with information from the container, including user- defined metadata in the container environment. Registrator
66. $ docker run -d --name nginx.0 -p 4443:443 -p 8000:80 progrium/nginx
67. [ { "ID": "hostname:nginx.0:443", "Name": "nginx-443", "Port": 4443, "IP": "192.168.1.102", "Tags": [], "Attrs": {}, }, { "ID": "hostname:nginx.0:80", "Name": "nginx-80", "Port": 8000, "IP": "192.168.1.102", "Tags": [], "Attrs": {} } ]
68. $ docker run -d --name redis.0 -p 10000:6379 \ -e "SERVICE_NAME=db" \ -e "SERVICE_TAGS=master,backups" \ -e "SERVICE_REGION=us2" dockerfile/redis
69. { "ID": "hostname:redis.0:6379", "Name": "db", "Port": 10000, "IP": "192.168.1.102", "Tags": ["master", "backups"], "Attrs": {"region": "us2"} }
70. Thank you! http://www.thewhitereview.org/interviews/ interview-with-douglas-coupland/