Both [static global configuration](/user-guide/kv-config/#static-configuration-in-key-value-store) and [dynamic](/user-guide/kv-config/#dynamic-configuration-in-key-value-store) configuration can be sorted in a Key-value store.
This section explains how to launch Træfɪk using a configuration loaded from a Key-value store.
Træfɪk supports several Key-value stores:
- [Consul](https://consul.io)
- [etcd](https://coreos.com/etcd/)
- [ZooKeeper](https://zookeeper.apache.org/)
- [boltdb](https://github.com/boltdb/bolt)
# Static configuration in Key-value store
We will see the steps to set it up with an easy example.
Note that we could do the same with any other Key-value Store.
## docker-compose file for Consul
The Træfɪk global configuration will be getted from a [Consul](https://consul.io) store.
First we have to launch Consul in a container.
The [docker-compose file](https://docs.docker.com/compose/compose-file/) allows us to launch Consul and four instances of the trivial app [emilevauge/whoamI](https://github.com/emilevauge/whoamI) :
To do that, we can send the Key-value pairs via [curl commands](https://www.consul.io/intro/getting-started/kv.html) or via the [Web UI](https://www.consul.io/intro/getting-started/ui.html).
- Remember to specify the indexes (`0`,`1`, `2`, ... ) under prefixes `/traefik/defaultentrypoints/` and `/traefik/entrypoints/https/tls/certificates/` in order to match the global configuration structure.
- Be careful to give the correct IP address and port on the key `/traefik/consul/endpoint`.
NB : Be careful to give the correct IP address and port in the flag `--consul.endpoint`.
## TLS support
So far, only [Consul](https://consul.io) and [etcd](https://coreos.com/etcd/) support TLS connections.
To set it up, we should enable [consul security](https://www.consul.io/docs/internals/security.html) (or [etcd security](https://coreos.com/etcd/docs/latest/security.html)).
Then, we have to provide CA, Cert and Key to Træfɪk using `consul` flags :
-`--consul.tls`
-`--consul.tls.ca=path/to/the/file`
-`--consul.tls.cert=path/to/the/file`
-`--consul.tls.key=path/to/the/file`
Or etcd flags :
-`--etcd.tls`
-`--etcd.tls.ca=path/to/the/file`
-`--etcd.tls.cert=path/to/the/file`
-`--etcd.tls.key=path/to/the/file`
Note that we can either give directly directly the file content itself (instead of the path to certificate) in a TOML file configuration.
Remember the command `traefik --help` to display the updated list of flags.
# Dynamic configuration in Key-value store
Following our example, we will provide backends/frontends rules to Træfɪk.
Note that this section is independent of the way Træfɪk got its static configuration.
It means that the static configuration can either come from the same Key-value store or from any other sources.
Træfɪk can watch the backends/frontends configuration changes and generate its configuration automatically.
Note that only backends/frontends rules are dynamic, the rest of the Træfɪk configuration stay static.
The [Etcd](https://github.com/coreos/etcd/issues/860) and [Consul](https://github.com/hashicorp/consul/issues/886) backends do not support updating multiple keys atomically. As a result, it may be possible for Træfɪk to read an intermediate configuration state despite judicious use of the `--providersThrottleDuration` flag. To solve this problem, Træfɪk supports a special key called `/traefik/alias`. If set, Træfɪk use the value as an alternative key prefix.
Given the key structure below, Træfɪk will use the `http://172.17.0.2:80` as its only backend (frontend keys have been omitted for brevity).
When an atomic configuration change is required, you may write a new configuration at an alternative prefix. Here, although the `/traefik_configurations/2/...` keys have been set, the old configuration is still active because the `/traefik/alias` key still points to `/traefik_configurations/1`:
Once the `/traefik/alias` key is updated, the new `/traefik_configurations/2` configuration becomes active atomically. Here, we have a 50% balance between the `http://172.17.0.3:80` and the `http://172.17.0.4:80` hosts while no traffic is sent to the `172.17.0.2:80` host:
The static Træfɪk configuration in a key-value store can be automatically created and updated, using the [`storeconfig` subcommand](/basics/#commands).
```bash
$ traefikstoreconfig[flags] ...
```
This command is here only to automate the [process which upload the configuration into the Key-value store](/user-guide/kv-config/#upload-the-configuration-in-the-key-value-store).
Træfɪk will not start but the [static configuration](/basics/#static-trfk-configuration) will be uploaded into the Key-value store.
