Rancher, l'orchestrateur qui vous veut du bien -- BreizhCamp2016
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L’introduction de docker en production se fait souvent petit à petit, en mode “nouveau format de packaging” plutôt qu’avec un orchestrateur docker. Les orchestrateurs comme Kubernetes ou Mesos peuvent faire peur de part leur potentielle complexité à être mis en oeuvre et intégrés dans une infrastructure existante. Nous découvrirons ensemble Rancher, un autre orchestrateur, plus facile à intégrer, mais tout aussi puissant. Nous verrons comment l'utiliser sans révolutionner son infrastructure et comment bénéficier de son utilisation dans des cas d'usage comme le “rolling upgrade” d'un service.
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Similaire à Rancher, l'orchestrateur qui vous veut du bien -- BreizhCamp2016
Similaire à Rancher, l'orchestrateur qui vous veut du bien -- BreizhCamp2016 (20)
Rancher, l'orchestrateur qui vous veut du bien -- BreizhCamp2016
- 1. BreizhCamp 2016 #BzhCmp #bzhrancher BreizhCamp 2016 #BzhCmp Rancher, le (petit) orchestrateur qui vous veut du bien Christophe Furmaniak - @cfurmaniak Youcef Yekhlef - @youcef_yekhlef
- 2. /us /me Christophe Furmaniak ✔ Twitter : @cfurmaniak ✔ Github : looztra ✔ Consultant Architecture et Culture DevOps chez Zenika ✔ Ex Atos Multimedia Atos Worldline Worldline ✔ (Très) Intéressé par la Gestion de la Configuration, les métriques, le cycle de construction, livraison et déploiement des applications ✔ Adepte de la tonte des Yaks Yak shaving : Any apparently useless activity which, by allowing you to overcome intermediate difficulties, allows you to solve a larger problem. ✔ Note : j'ai l'air grincheux, mes slides ne sont pas très esthétiques, je suis au courant
- 3. /youcef
- 4. Le contenu de la prez ✔ L'application guestbook ✔ Des containers en mode 'de base' ✔ Level Up : utilisons un orchestrateur ✔ Rancher ? ✔ Démo : Rancher + containers en mode 'de base' ✔ Démo : Guestbook v1 powered by Rancher ✔ Démo : Upgrade de service méthode 1 ('rolling upgrade') ✔ Démo : Upgrade de service méthode 2 ('blue/green')
- 5. Où en est-on ? ✔ L'application guestbook ✔ Des containers en mode 'de base' ✔ Level Up : utilisons un orchestrateur ✔ Rancher ? ✔ Démo : Rancher + containers en mode 'de base' ✔ Démo : Guestbook v1 powered by Rancher ✔ Démo : Upgrade de service méthode 1 ('rolling upgrade') ✔ Démo : Upgrade de service méthode 2 ('blue/green')
- 6. L'application Guestbook ✔ Inspirée de l'exemple kubernetes / guestbook ✔ Un stockage de données à base : ✔ D'un redis master (write) ✔ De deux redis en mode slave (read) ✔ Une couche API service à base de SpringBoot ✔ Une couche Front à base html+js dans un nginx
- 8. Où en est-on ? ✔ L'application guestbook ✔ Des containers en mode 'de base' ✔ Level Up : utilisons un orchestrateur ✔ Rancher ? ✔ Démo : Rancher + containers en mode 'de base' ✔ Démo : Guestbook v1 powered by Rancher ✔ Démo : Upgrade de service méthode 1 ('rolling upgrade') ✔ Démo : Upgrade de service méthode 2 ('blue/green')
- 9. L'application Guestbook #1 #2 #1 #2 master s#1 s#2 LB Front LB Middle LB Back (read) Front Middle Back
- 10. Docker en mode 'de base' ✔ Containers lancés avec ansible (par exemple), ou avec des scripts 'maison', voire à la main (ouch) ✔ Pas de communication entre les containers hébergés sur 2 hosts différents (ex : pre-docker 1.9) ✔ Port mapping en dur ✔ docker run -d -p 8000:80 ns/frontend ✔ docker run -d -p 8080:8080 ns/api-server ✔ docker run -d -p 6379:6379 ns/redis-master ✔ docker run -d -p 6380:6379 ns/redis-slave
- 11. Docker en mode 'de base' ✔ Affectation manuelle des containers sur les hosts ✔ Comment bien gérer la montée en charge ? ✔ Comment bien redémarrer les containers en cas de pb ? ✔ Comment gérer la maintenance des hosts ? ✔ Au démarrage, 7 containers + 3 loadbalancers à gérer : ✔ et si l'application se complexifie ? ✔ comment gérer les mises à jour ?
- 12. Et vos ops dans tout ça ?
- 13. Où en est-on ? ✔ L'application guestbook ✔ Des containers en mode 'de base' ✔ Level Up : utilisons un orchestrateur ✔ Rancher ? ✔ Démo : Rancher + containers en mode 'de base' ✔ Démo : Guestbook v1 powered by Rancher ✔ Démo : Upgrade de service méthode 1 ('rolling upgrade') ✔ Démo : Upgrade de service méthode 2 ('blue/green')
- 14. Un orchestrateur ? L'orchestration : ✔ Scheduling (Affectation) ✔ Gestion des erreurs ✔ Provisionning des hosts ✔ Services : ✔ Load balancing ✔ Discovery ✔ ... cf blog Octo : la bataille sanglante des orchestrateurs
- 15. Autrement dit : ✔ Un orchestrateur : ✔ permet de “scaler” l’utilisation de docker dans un environnement plus conséquent ✔ apporte des mécanismes de répartition de charge et des règles de gestion : ✔ le container A ne doit pas tourner sur le même host que le container B ✔ le container C doit tourner sur tous les hosts existants qui portent le label “front” ✔ permet de redémarrer automatiquement le container D s’il n’est plus fonctionnel ✔ éventuellement : gérer la communication réseau entre les différents containers des différents hosts
- 16. Des orchestrateurs ✔ Fleet (CoreOS) ✔ Docker Swarm ✔ Kubernetes ✔ Rancher ✔ Mesos ✔ Marathon (Mesos Framework) ✔ Titus (Netflix, Mesos Framework) ✔ Nomad (Hashicorp) ✔ Deis (Heroku like) ✔ RedHat Openshift V3 (Kubernetes) ✔ Tectonic (CoreOS/Kubernetes) ✔ Mantl (Mesos & Kubernetes) ✔ ...
- 17. Où en est-on ? ✔ L'application guestbook ✔ Des containers en mode 'de base' ✔ Level Up : utilisons un orchestrateur ✔ Rancher ? ✔ Démo : Rancher + containers en mode 'de base' ✔ Démo : Guestbook v1 powered by Rancher ✔ Démo : Upgrade de service méthode 1 ('rolling upgrade') ✔ Démo : Upgrade de service méthode 2 ('blue/green')
- 18. Rancher par RancherLabs ✔ RancherLabs (http://rancher.com @Rancher_Labs): ✔ Créée par des anciens de Citrix Systems ✔ Cupertino (Californie) + Mesa (Arizona) ✔ Rancher ? Cattle vs Pet paradigme ✔ Premiers commits sur GH en nov 2014 ✔ 2 produits : Rancher et RancherOS ● « Rancher is a complete platform for running Docker applications in production » ● « RancherOS is a 20mb Linux distro that runs the entire OS as Docker containers »
- 19. Rancher : fonctionnalités ✔ Communication des containers cross-host (overlay network utilisant un tunnel Ipsec) ✔ Container scheduling ✔ Enregistrement/Découverte de services ✔ Loadbalancers ✔ Service DNS distribué + Service Metadata ✔ Healthchecks (tcp connection, http 2xx/3xx) ✔ Haute Dispo des services ✔ Mise à jour de services ('rolling upgrade','Blue/Green') ✔ Rancher-compose ✔ Sidekicks (=~ pods kubernetes)
- 20. Où en est-on ? ✔ L'application guestbook ✔ Des containers en mode 'de base' ✔ Level Up : utilisons un orchestrateur ✔ Rancher ? ✔ Démo : Rancher + containers en mode 'de base' ✔ Démo : Guestbook v1 powered by Rancher ✔ Démo : Upgrade de service méthode 1 ('rolling upgrade') ✔ Démo : Upgrade de service méthode 2 ('blue/green')
- 21. Démo #1 ✔ Rancher + containers en mode legacy ✔ Objectifs : ✔ Installation de rancher ✔ Visualisation des containers existants (non gérés par rancher)
- 22. Où en est-on ? ✔ L'application guestbook ✔ Des containers en mode 'de base' ✔ Level Up : utilisons un orchestrateur ✔ Rancher ? ✔ Démo : Rancher + containers en mode 'de base' ✔ Démo : Guestbook v1 powered by Rancher ✔ Démo : Upgrade de service méthode 1 ('rolling upgrade') ✔ Démo : Upgrade de service méthode 2 ('blue/green')
- 23. Démo #2 ✔ L'application Guestbook v1 déployée avec Rancher ✔ Objectifs : ✔ Un guestbook v1 déployé manuellement Note : DNS en round robin pré-configuré sur les 2 hosts « front »
- 24. Où en est-on ? ✔ L'application guestbook ✔ Des containers en mode 'de base' ✔ Level Up : utilisons un orchestrateur ✔ Rancher ? ✔ Démo : Rancher + containers en mode 'de base' ✔ Démo : Guestbook v1 powered by Rancher ✔ Démo : Upgrade de service méthode 1 ('rolling upgrade') ✔ Démo : Upgrade de service méthode 2 ('blue/green')
- 26. Où en est-on ? ✔ L'application guestbook ✔ Des containers en mode 'de base' ✔ Level Up : utilisons un orchestrateur ✔ Rancher ? ✔ Démo : Rancher + containers en mode 'de base' ✔ Démo : Guestbook v1 powered by Rancher ✔ Démo : Upgrade de service méthode 1 ('rolling upgrade') ✔ Démo : Upgrade de service méthode 2 ('blue/green')
- 28. Où en est-on ? ✔ L'application guestbook ✔ Des containers en mode 'de base' ✔ Level Up : utilisons un orchestrateur ✔ Rancher ? ✔ Démo : Rancher + containers en mode 'de base' ✔ Démo : Guestbook v1 powered by Rancher ✔ Démo : Upgrade de service méthode 1 ('rolling upgrade') ✔ Démo : Upgrade de service méthode 2 ('blue/green')
- 30. goulennata ?
Notes de l'éditeur
- http://docs.rancher.com/rancher/concepts/#networking NETWORKING Rancher supports cross-host container communication by implementing a simple and secure overlay network using IPsec tunneling. To leverage this capability, a container launched through Rancher must select “Managed” for its network mode or if launched through Docker, provide an extra label “–label io.rancher.container.network=true”. Most of Rancher’s network features, such as load balancer or DNS service, require the container to be in the managed network. Under Rancher’s network, a container will be assigned both a Docker bridge IP (172.17.0.0/16) and a Rancher managed IP (10.42.0.0/16) on the default docker0 bridge. Containers within the same environment are then routable and reachable via the managed network. SERVICE DISCOVERY Rancher adopts the standard Docker Compose terminology for services and defines a basic service as one or more containers created from the same Docker image. Once a service (consumer) is linked to another service (producer) within the same stack, a DNS record mapped to each container instance is automatically created and discoverable by containers from the “consuming” service. Other benefits of creating a service under Rancher include: Service High Availability (HA) - the ability to have Rancher automatically monitor container states and maintain a service’s desired scale. Health Monitoring - the ability to set basic monitoring thresholds for container health. Add Load Balancers - the ability to add a simple load balancer for your services using HAProxy. Add External Services - the ability to add any-IP as a service to be discovered. Add Service Alias - the ability to add a DNS record for your services to be discovered. LOAD BALANCER Rancher implements a managed load balancer using HAProxy that can be manually scaled to multiple hosts. A load balancer can be used to distribute network and application traffic to individual containers by directly adding them or “linked” to a basic service. A basic service that is “linked” will have all its underlying containers automatically registered as load balancer targets by Rancher. DISTRIBUTED DNS SERVICE Rancher implements a distributed DNS service by using its own light-weight DNS server coupled with a highly available control plane. Each healthy container is automatically added to the DNS service when linked to another service or added to a Service Alias. When queried by the service name, the DNS service returns a randomized list of IP addresses of the healthy containers implementing that service. By default, all services within the same stack are added to the DNS service without requiring explicit links. You can resolve containers within the same stacks by the service names. If you need a custom DNS name for your service, that is different from your service name, you will be required to use a link to get the custom DNS name. Links are still required for load balancers to target services. Links are still required if a Service Alias is used. To make services resolvable that are in different stacks, you will need to link them explicitly. Because Rancher’s overlay networking provides each container with a distinct IP address, you do not need to deal with port mappings and do not need to handle situations like duplicated services listening on different ports. As a result, a simple DNS service is adequate for handling service discovery. HEALTH CHECKS Rancher implements a health monitoring system by running managed network agent’s across it’s hosts to co-ordinate the distributed health checking of containers and services. These network agents internally utilize HAProxy to validate the health status of your applications. When health checks are enabled either on an individual container or a service, each container is then monitored by up to three network agents running on hosts separate to that containers parent host. The container is considered healthy if at least one HAProxy instance reports a “passed” health check. SERVICE HA Rancher constantly monitors the state of your containers within a service and actively manages to ensure the desired scale of the service. This can be triggered when there are fewer (or even more) healthy containers than the desired scale of your service, a host becomes unavailable, a container fails, or is unable to meet a health check. SERVICE UPGRADE Rancher supports the notion of service upgrades by allowing users to either load balance or apply a service alias for a given service. By leveraging either Rancher features, it creates a static destination for existing workloads that require that service. Once this is established, the underlying service can be cloned from Rancher as a new service, validated through isolated testing, and added to either the load balancer or service alias when ready. The existing service can be removed when obsolete. Subsequently, all the network or application traffic are automatically distributed to the new service. RANCHER COMPOSE Rancher implements and ships a command-line tool called rancher-compose that is modeled after docker-compose. It takes in the same docker-compose.yml templates and deploys the Stacks onto Rancher. The rancher-compose tool additionally takes in a rancher-compose.yml file which extends docker-compose.yml to allow specifications of attributes such as scale, load balancing rules, health check policies, and external links not yet currently supported by docker-compose. For more information, see rancher-compose. STACKS A Rancher stack mirrors the same concept as a docker-compose project. It represents a group of services that make up a typical application or workload. CONTAINER SCHEDULING Rancher supports container scheduling policies that are modeled closely after Docker Swarm. They include scheduling based on: port conflicts shared volumes host tagging shared network stack: –net=container:dependency strict and soft affinity/anti-affinity rules by using both env var (Swarm) and labels (Rancher) In addition, Rancher supports scheduling service triggers that allow users to specify rules, such as on “host add” or “host label”, to automatically scale services onto hosts with specific labels. For more information on Container Scheduling and comparison matrix of Rancher’s scheduling and Docker Swarm, see rancher-compose SIDEKICKS Rancher supports the colocation, scheduling, and lock step scaling of a set of services by allowing users to group these services by using the notion of sidekicks. A service with one or more sidekicks is typically created to support shared volumes (i.e. --volumes_from) and networking (i.e. --net=container) between containers. For more information, see sidekicks with rancher-compose. METADATA SERVICES Rancher offers data for both your services and containers. This data can be used to manage your running Docker instances in the form of a metadata service accessed directly through a HTTP based API. These data can include static information when creating your Docker containers, Rancher Services, or runtime data such as discovery information about peer containers within the same service.