diff options
Diffstat (limited to 'doc/book/src/getting_started/cluster.md')
| -rw-r--r-- | doc/book/src/getting_started/cluster.md | 72 |
1 files changed, 65 insertions, 7 deletions
diff --git a/doc/book/src/getting_started/cluster.md b/doc/book/src/getting_started/cluster.md index a17bf14e..af6e8f10 100644 --- a/doc/book/src/getting_started/cluster.md +++ b/doc/book/src/getting_started/cluster.md @@ -1,14 +1,72 @@ # Configure a cluster +*We use a command named `garagectl` which is in fact an alias you must define as explained in the [Control the daemon](./daemon.md) section.* + +In this section, we will inform garage of the disk space available on each node of the cluster +as well as the site (think datacenter) of each machine. + ## Test cluster +As this part is not relevant for a test cluster, you can use this one-liner to create a basic topology: + +```bash +garagectl status | grep UNCONFIGURED | grep -Po '^[0-9a-f]+' | while read id; do + garagectl node configure -d dc1 -n 10 $id +done +``` + ## Real-world cluster -For our example, we will suppose we have the following infrastructure: +For our example, we will suppose we have the following infrastructure (Tokens, Identifier and Datacenter are specific values to garage described in the following): + +| Location | Name | Disk Space | `Tokens` | `Identifier` | `Datacenter` | +|----------|---------|------------|----------|--------------|--------------| +| Paris | Mercury | 1 To | `100` | `8781c5` | `par1` | +| Paris | Venus | 2 To | `200` | `2a638e` | `par1` | +| London | Earth | 2 To | `200` | `68143d` | `lon1` | +| Brussels | Mars | 1.5 To | `150` | `212f75` | `bru1` | + +### Identifier + +After its first launch, garage generates a random and unique identifier for each nodes, such as: + +``` +8781c50c410a41b363167e9d49cc468b6b9e4449b6577b64f15a249a149bdcbc +``` + +Often a shorter form can be used, containing only the beginning of the identifier, like `8781c5`, +which identifies the server "Mercury" located in "Paris" according to our previous table. + +The most simple way to match an identifier to a node is to run: + +``` +garagectl status +``` + +It will display the IP address associated with each node; from the IP address you will be able to recognize the node. + +### Tokens + +Garage reasons on an arbitrary metric about disk storage that is named "tokens". +The number of tokens must be proportional to the disk space dedicated to the node. +Additionaly, ideally the number of tokens must be in the order of magnitude of 100 +to provide a good trade-off between data load balancing and performances (*this sentence must be verified, it may be wrong*). + +Here we chose 1 token = 10 Go but you are free to select the value that best fit your needs. + +### Datacenter + +Datacenter are simply a user-chosen identifier that identify a group of server that are located in the same place. +It is up to the system administrator deploying garage to identify what does "the same place" means. +Behind the scene, garage will try to store the same data on different sites to provide high availability despite a data center failure. + +### Inject the topology + +Given the information above, we will configure our cluster as follow: -| Location | Name | IP Address | Disk Space | -|----------|---------|------------|------------| -| Paris | Mercury | fc00:1::1 | 1 To | -| Paris | Venus | fc00:1::2 | 2 To | -| London | Earth | fc00:1::2 | 2 To | -| Brussels | Mars | fc00:B::1 | 1.5 To | +``` +garagectl node configure --datacenter par1 -n 100 -t mercury 8781c5 +garagectl node configure --datacenter par1 -n 200 -t venus 2a638e +garagectl node configure --datacenter lon1 -n 200 -t earth 68143d +garagectl node configure --datacenter bru1 -n 150 -t mars 212f75 +``` |