diff --git a/sysadm/mirror-operations/docker.rst b/sysadm/mirror-operations/docker.rst index 3b43a29..3b7fb47 100644 --- a/sysadm/mirror-operations/docker.rst +++ b/sysadm/mirror-operations/docker.rst @@ -1,501 +1,504 @@ .. _mirror_docker: Deploy a Software Heritage stack with docker deploy =================================================== .. admonition:: Intended audience :class: important mirror operators Prerequisities -------------- We assume that you have a properly set up docker swarm cluster with support for the `docker stack deploy `_ command, e.g.: .. code-block:: bash ~/swh-docker$ docker node ls ID HOSTNAME STATUS AVAILABILITY MANAGER STATUS ENGINE VERSION py47518uzdb94y2sb5yjurj22 host2 Ready Active 18.09.7 n9mfw08gys0dmvg5j2bb4j2m7 * host1 Ready Active Leader 18.09.7 Note: on some systems (centos for example), making docker swarm work requires some permission tuning regarding the firewall and selinux. Please refer to `the upstream docker-swarm documentation `_. -In the following how-to, we will assume that the service `STACK` name is `swh` -(this name is the last argument of the `docker stack deploy` command below). +In the following how-to, we will assume that the service ``STACK`` name is ``swh`` +(this name is the last argument of the :command:`docker stack deploy` command below). Several preparation steps will depend on this name. We also use `docker-compose `_ to merge compose files, so make sure it is available on your system. You also need to clone the git repository: https://forge.softwareheritage.org/source/swh-docker Set up volumes -------------- -Before starting the `swh` service, you will certainly want to specify where the +Before starting the ``swh`` service, you will certainly want to specify where the data should be stored on your docker hosts. By default docker will use docker volumes for storing databases and the content of -the objstorage (thus put them in `/var/lib/docker/volumes`). +the objstorage (thus put them in :file:`/var/lib/docker/volumes`). **Optional:** if you want to specify a different location to put the data in, you should create the docker volumes before starting the docker service. For -example, the `objstorage` service uses a volume named `_objstorage`: +example, the ``objstorage`` service uses a volume named ``_objstorage``: .. code-block:: bash ~/swh-docker$ docker volume create -d local \ --opt type=none \ --opt o=bind \ --opt device=/data/docker/swh-objstorage \ swh_objstorage -If you want to deploy services like the `objstorage` on several hosts, you will need a +If you want to deploy services like the ``objstorage`` on several hosts, you will need a shared storage area in which blob objects will be stored. Typically a NFS storage can be used for this, or any existing docker volume driver like `REX-Ray `_. This is not covered in this documentation. Please read the documentation of docker volumes to learn how to use such a device/driver as volume provider for docker. -Note that the provided `base-services.yaml` file has placement constraints for the -`db-storage`, `db-web` and `objstorage` containers, that depend on the availability of -specific volumes (respectively `_storage-db`, `_web-db` and -`_objstorage`). These services are pinned to specific nodes using labels named -`org.softwareheritage.mirror.volumes.` (e.g. -`org.softwareheritage.mirror.volumes.objstorage`). +Note that the provided :file:`base-services.yaml` file has placement constraints for the +``db-storage``, ``db-web`` and ``objstorage`` containers, that depend on the availability of +specific volumes (respectively ``_storage-db``, ``_web-db`` and +``_objstorage``). These services are pinned to specific nodes using labels named +``org.softwareheritage.mirror.volumes.`` (e.g. +``org.softwareheritage.mirror.volumes.objstorage``). When you create a local volume for a given container, you should add the relevant label to the docker swarm node metadata with: .. code-block:: bash docker node update \ --label-add org.softwareheritage.mirror.volumes.objstorage=true \ You have to set the node labels, or to adapt the placement constraints to your local requirements, for the services to start. Managing secrets ---------------- -Shared passwords (between services) are managed via `docker secret`. Before +Shared passwords (between services) are managed via :command:`docker secret`. Before being able to start services, you need to define these secrets. -Namely, you need to create a `secret` for: +Namely, you need to create a ``secret`` for: -- `swh-mirror-db-postgres-password` -- `swh-mirror-web-postgres-password` +- ``swh-mirror-db-postgres-password`` +- ``swh-mirror-web-postgres-password`` For example: .. code-block:: bash ~/swh-docker$ xkcdpass -d- | docker secret create swh-mirror-db-postgres-password - [...] Spawning the swh base services ------------------------------ If you haven't done it yet, clone this git repository: .. code-block:: bash ~$ git clone https://forge.softwareheritage.org/source/swh-docker.git ~$ cd swh-docker This repository provides the docker compose/stack manifests to deploy all the relevant services. .. note:: These manifests use a set of docker images `published in the docker hub `_. By default, the manifests - will use the `latest` version of these images, but for production uses, you should - set the `SWH_IMAGE_TAG` environment variable to pin them to a specific version. + will use the ``latest`` version of these images, but for production uses, you should + set the ``SWH_IMAGE_TAG`` environment variable to pin them to a specific version. -To specify the tag to be used, simply set the SWH_IMAGE_TAG environment variable, like -so: +To specify the tag to be used, simply set the :envvar:`SWH_IMAGE_TAG` +environment variable: .. code-block:: bash ~/swh-docker$ export SWH_IMAGE_TAG=20211022-121751 You can then spawn the base services using the following command: .. code-block:: bash ~/swh-docker$ docker stack deploy -c base-services.yml swh Creating network swh_default Creating config swh_storage Creating config swh_objstorage Creating config swh_nginx Creating config swh_web Creating service swh_grafana Creating service swh_prometheus-statsd-exporter Creating service swh_web Creating service swh_objstorage Creating service swh_db-storage Creating service swh_memcache Creating service swh_storage Creating service swh_nginx Creating service swh_prometheus ~/swh-docker$ docker service ls ID NAME MODE REPLICAS IMAGE PORTS tc93talbe2tg swh_db-storage global 1/1 postgres:13 42q5jtxsh029 swh_db-web global 1/1 postgres:13 rtlz62ok6s96 swh_grafana replicated 1/1 grafana/grafana:latest jao3rt0et17n swh_memcache replicated 1/1 memcached:latest rulxakqgu2ko swh_nginx replicated 1/1 nginx:latest *:5081->5081/tcp q560pvw3q3ls swh_objstorage replicated 2/2 softwareheritage/base:20211022-121751 a2h3ltaqdt56 swh_prometheus global 1/1 prom/prometheus:latest lm24et9gjn2k swh_prometheus-statsd-exporter replicated 1/1 prom/statsd-exporter:latest gwqinrao5win swh_storage replicated 2/2 softwareheritage/base:20211022-121751 7g46blmphfb4 swh_web replicated 1/1 softwareheritage/web:20211022-121751 This will start a series of containers with: - an objstorage service, - a storage service using a postgresql database as backend, - a web app front end using a postgresql database as backend, - a memcache for the web app, - a prometheus monitoring app, - a prometeus-statsd exporter, - a grafana server, - an nginx server serving as reverse proxy for grafana and swh-web. using the pinned version of the docker images. The nginx frontend will listen on the 5081 port, so you can use: - http://localhost:5081/ to navigate your local copy of the archive, - http://localhost:5081/grafana/ to explore the monitoring probes (log in with admin/admin). .. warning:: - Please make sure that the `SWH_IMAGE_TAG` variable is properly set for any later - `docker stack deploy` command you type, otherwise all the running containers will be - recreated using the ':latest' image (which might **not** be the latest available + Please make sure that the :envvar:`SWH_IMAGE_TAG` variable is properly set for any later + :command:`docker stack deploy` command you type, otherwise all the running containers will be + recreated using the ``:latest`` image (which might **not** be the latest available version, nor consistent among the docker nodes on your swarm cluster). Updating a configuration ------------------------ -Configuration files are exposed to docker services via the ``docker -config`` system. Unfortunately, docker does not support updating these config +Configuration files are exposed to docker services via the :command:`docker config` +system. Unfortunately, docker does not support updating these config objects. The usual method to update a config in a service is: - create a new config entry with updated config content, - update targeted running services to replace the original config entry by the new one, - destroy old (now unused) docker config objects. -For example, if you edit the file `conf/storage.yml`: +For example, if you edit the file :file:`conf/storage.yml`: .. code-block:: bash ~/swh-docker$ docker config create storage-2 conf/storage.yml h0m8jvsacvpl71zdcq3wnud6c ~/swh-docker$ docker service update \ --config-rm storage \ --config-add source=storage-2,target=/etc/softwareheritage/config.yml \ swh_storage swh_storage overall progress: 2 out of 2 tasks verify: Service converged ~/swh-docker$ docker config rm storage .. Warning:: this procedure will update the live configuration of the service stack, which will then be out of sync with the stack described in the compose file used to create the stack. This needs to be kept - in mind if you try to apply the stack configuration using ``docker - stack deploy`` later on. However if you destroy the unused config - entry as suggested above, an execution of the ``docker stack - deploy`` will not break anything (just recreate containers) since - it will recreate original config object with the proper content. + in mind if you try to apply the stack configuration using + :command:`docker stack deploy` later on. However if you destroy + the unused config entry as suggested above, an execution of the + :command:`docker stack deploy` will not break anything (just recreate + containers) since it will recreate original config object with the + proper content. See https://docs.docker.com/engine/swarm/configs/ for more details on how to use the config system in a docker swarm cluster. -Note that the ``docker service update`` command can be used for many other +Note that the :command:`docker service update` command can be used for many other things, for example it can be used to change the debug level of a service: .. code-block:: bash ~/swh-docker$ docker service update --env-add LOG_LEVEL=DEBUG swh_storage Then you can revert to the previous setup using: .. code-block:: bash ~/swh-docker$ docker service update --rollback swh_storage -See the documentation of the `swh service update command +See the documentation of the `swh service update `_ -for more details. +command for more details. Updating an image ----------------- When a new version of the softwareheritage image is published, running services must updated to use it. In order to prevent inconsistency caveats due to dependency in deployed versions, we recommend that you deploy the new image on all running services at once. This can be done as follow: .. code-block:: bash ~/swh-docker$ export SWH_IMAGE_TAG= ~/swh-docker$ docker stack deploy -c base-services.yml swh Note that this will reset the replicas config to their default values. If you want to update only a specific service, you can also use (here for a replayer service): .. code-block:: bash ~/swh-docker$ docker service update --image \ softwareheritage/replayer:${SWH_IMAGE_TAG} \ swh_graph-replayer Set up the mirroring components =============================== A Software Heritage mirror consists in base Software Heritage services, as described above, without any worker related to web scraping nor source code repository loading. Instead, filling local storage and objstorage is the -responsibility of kafka based `replayer` services: +responsibility of kafka based ``replayer`` services: -- the `graph replayer` which is in charge of filling the storage (aka the +- the ``graph replayer`` which is in charge of filling the storage (aka the graph), and -- the `content replayer` which is in charge of filling the object storage. +- the ``content replayer`` which is in charge of filling the object storage. Examples of docker deploy files and configuration files are provided in -the `graph-replayer.yml` deploy file for replayer services -using configuration from yaml files in `conf/graph-replayer.yml`. +the :file:`graph-replayer.yml` deploy file for replayer services +using configuration from yaml files in :file:`conf/graph-replayer.yml`. Copy these example files as plain yaml ones then modify them to replace the XXX markers with proper values (also make sure the kafka server list is up to date). The parameters to check/update are: -- `journal_client.brokers`: list of kafka brokers. -- `journal_client.group_id`: unique identifier for this mirroring session; +- ``journal_client.brokers``: list of kafka brokers. +- ``journal_client.group_id``: unique identifier for this mirroring session; you can choose whatever you want, but changing this value will make kafka start consuming messages from the beginning; kafka messages are dispatched - among consumers with the same `group_id`, so in order to distribute the - load among workers, they must share the same `group_id`. -- `journal_client."sasl.username"`: kafka authentication username. -- `journal_client."sasl.password"`: kafka authentication password. + among consumers with the same ``group_id``, so in order to distribute the + load among workers, they must share the same ``group_id``. +- ``journal_client.sasl.username``: kafka authentication username. +- ``journal_client.sasl.password``: kafka authentication password. Then you need to merge the compose files "by hand" (due to this still `unresolved `_ `bugs `_). For this we will use `docker compose `_ as helper tool to merge the compose files. -To merge 2 (or more) compose files together, typically `base-services.yml` with +To merge 2 (or more) compose files together, typically :file:`base-services.yml` with a mirror-related file: .. code-block:: bash ~/swh-docker$ docker-compose \ -f base-services.yml \ -f graph-replayer-override.yml \ config > mirror.yml -Then use this generated file as argument of the `docker stack deploy` command, e.g.: +Then use this generated file as argument of the :command:`docker stack deploy` +command, e.g.: .. code-block:: bash ~/swh-docker$ docker stack deploy -c mirror.yml swh Graph replayer -------------- To run the graph replayer component of a mirror: .. code-block:: bash ~/swh-docker$ cd conf ~/swh-docker/conf$ cp graph-replayer.yml.example graph-replayer.yml ~/swh-docker/conf$ $EDITOR graph-replayer.yml ~/swh-docker/conf$ cd .. -Once you have properly edited the `conf/graph-replayer.yml` config file, you can -start these services with: +Once you have properly edited the :file:`conf/graph-replayer.yml` config file, +you can start these services with: .. code-block:: bash ~/swh-docker$ docker-compose \ -f base-services.yml \ -f graph-replayer-override.yml \ config > stack-with-graph-replayer.yml ~/swh-docker$ docker stack deploy \ -c stack-with-graph-replayer.yml \ swh [...] You can check everything is running with: .. code-block:: bash ~/swh-docker$ docker stack ls NAME SERVICES ORCHESTRATOR swh 11 Swarm ~/swh-docker$ docker service ls ID NAME MODE REPLICAS IMAGE PORTS tc93talbe2tg swh_db-storage global 1/1 postgres:13 42q5jtxsh029 swh_db-web global 1/1 postgres:13 rtlz62ok6s96 swh_grafana replicated 1/1 grafana/grafana:latest 7hvn66um77wr swh_graph-replayer replicated 4/4 softwareheritage/replayer:20211022-121751 jao3rt0et17n swh_memcache replicated 1/1 memcached:latest rulxakqgu2ko swh_nginx replicated 1/1 nginx:latest *:5081->5081/tcp q560pvw3q3ls swh_objstorage replicated 2/2 softwareheritage/base:20211022-121751 a2h3ltaqdt56 swh_prometheus global 1/1 prom/prometheus:latest lm24et9gjn2k swh_prometheus-statsd-exporter replicated 1/1 prom/statsd-exporter:latest gwqinrao5win swh_storage replicated 2/2 softwareheritage/base:20211022-121751 7g46blmphfb4 swh_web replicated 1/1 softwareheritage/web:20211022-121751 If everything is OK, you should have your mirror filling. Check docker logs: .. code-block:: bash ~/swh-docker$ docker service logs swh_graph-replayer [...] or: .. code-block:: bash ~/swh-docker$ docker service logs --tail 100 --follow swh_graph-replayer [...] Content replayer ---------------- Similarly, to run the content replayer: .. code-block:: bash ~/swh-docker$ cd conf ~/swh-docker/conf$ cp content-replayer.yml.example content-replayer.yml ~/swh-docker/conf$ # edit content-replayer.yml files ~/swh-docker/conf$ cd .. -Once you have properly edited the `conf/content-replayer.yml` config file, you can +Once you have properly edited the :file:`conf/content-replayer.yml` config file, you can start these services with: .. code-block:: bash ~/swh-docker$ docker-compose \ -f base-services.yml \ -f content-replayer-override.yml \ config > content-replayer.yml ~/swh-docker$ docker stack deploy \ -c content-replayer.yml \ swh [...] Full mirror ----------- Putting all together is just a matter of merging the 3 compose files: .. code-block:: bash ~/swh-docker$ docker-compose \ -f base-services.yml \ -f graph-replayer-override.yml \ -f content-replayer-override.yml \ config > mirror.yml ~/swh-docker$ docker stack deploy \ -c mirror.yml \ swh [...] Getting your deployment production-ready ======================================== docker-stack scaling -------------------- -In order to scale up a replayer service, you can use the `docker scale` command. For example: +In order to scale up a replayer service, you can use the :command:`docker +scale` command. For example: .. code-block:: bash ~/swh-docker$ docker service scale swh_graph-replayer=4 [...] will start 4 copies of the graph replayer service. Notes on the throughput of the mirroring process ------------------------------------------------ - One graph replayer service requires a steady 500MB to 1GB of RAM to run, so make sure you have properly sized machines for running these replayer containers, and to monitor these. - The graph replayer containers will require sufficient network bandwidth for the kafka traffic (this can easily peak to several hundreds of megabits per second, and the total volume of data fetched will be multiple tens of terabytes). - The biggest kafka topics are directory, revision and content, and will take the longest to initially replay. Operational concerns for the Storage database --------------------------------------------- -The overall throughput of the mirroring process will depend heavily on the `swh_storage` -service, and on the performance of the underlying `swh_db-storage` database. You will +The overall throughput of the mirroring process will depend heavily on the ``swh_storage`` +service, and on the performance of the underlying ``swh_db-storage`` database. You will need to make sure that your database is `properly tuned `_. You may also want to deploy your database directly to a bare-metal server rather than have it managed within the docker stack. To do so, you will have to: - modify the (merged) configuration of the docker stack to drop references to the - `db-storage` service (itself, and as dependency for the `storage` service) + ``db-storage`` service (itself, and as dependency for the ``storage`` service) - ensure that docker containers deployed in your swarm are able to connect to your external database server -- override the environment variables of the `storage` service to reference the external +- override the environment variables of the ``storage`` service to reference the external database server and dbname