# Installing

NATS philosophy is simplicity. Installation is just decompressing a zip file and copying the binary to an appropriate directory; you can also use your favorite package manager. Here's a list of different ways you can install or run NATS:

* [Docker](installation.md#installing-via-docker)
* [Kubernetes](installation.md#installing-on-kubernetes-with-nats-operator)
* [Package Manager](installation.md#installing-via-a-package-manager)
* [Release Zip](installation.md#downloading-a-release-build)
* [Development Build](installation.md#installing-from-the-source)

## Installing via Docker

With Docker you can install the server easily without scattering binaries and other artifacts on your system. The only pre-requisite is to [install docker](https://docs.docker.com/install).

```text
> docker pull nats:latest
latest: Pulling from library/nats
Digest: sha256:0c98cdfc4332c0de539a064bfab502a24aae18ef7475ddcc7081331502327354
Status: Image is up to date for nats:latest
docker.io/library/nats:latest
```

To run NATS on Docker:

```text
> docker run -p 4222:4222 -ti nats:latest
[1] 2019/05/24 15:42:58.228063 [INF] Starting nats-server version #.#.#
[1] 2019/05/24 15:42:58.228115 [INF] Git commit [#######]
[1] 2019/05/24 15:42:58.228201 [INF] Starting http monitor on 0.0.0.0:8222
[1] 2019/05/24 15:42:58.228740 [INF] Listening for client connections on 0.0.0.0:4222
[1] 2019/05/24 15:42:58.228765 [INF] Server is ready
[1] 2019/05/24 15:42:58.229003 [INF] Listening for route connections on 0.0.0.0:6222
```

More information on [containerized NATS is available here](nats_docker/).

## Installing on Kubernetes with NATS Operator

Installation via the NATS Operator is beyond this tutorial. You can read about the [NATS Operator](https://github.com/nats-io/nats-operator) here.

## Installing via a Package Manager

On Windows:

```text
> choco install nats-server
```

On Mac OS:

```text
> brew install nats-server
```

To test your installation \(provided the executable is visible to your shell\):

```text
> nats-server
[41634] 2019/05/13 09:42:11.745919 [INF] Starting nats-server version 2.0.0
[41634] 2019/05/13 09:42:11.746240 [INF] Listening for client connections on 0.0.0.0:4222
...
[41634] 2019/05/13 09:42:11.746249 [INF] Server id is NBNYNR4ZNTH4N2UQKSAAKBAFLDV3PZO4OUYONSUIQASTQT7BT4ZF6WX7
[41634] 2019/05/13 09:42:11.746252 [INF] Server is ready
```

## Downloading a Release Build

You can find the latest release of nats-server [here](https://github.com/nats-io/nats-server/releases/latest).

Download the zip file matching your systems architecture, and unzip. For this example, assuming version 2.0.0 of the server and a Linux AMD64:

```text
> curl -L https://github.com/nats-io/nats-server/releases/download/v2.0.0/nats-server-v2.0.0-linux-amd64.zip -o nats-server.zip

> unzip nats-server.zip -d nats-server
Archive:  nats-server.zip
   creating: nats-server-v2.0.0-linux-amd64/
  inflating: nats-server-v2.0.0-linux-amd64/README.md
  inflating: nats-server-v2.0.0-linux-amd64/LICENSE
  inflating: nats-server-v2.0.0-linux-amd64/nats-server

> sudo cp nats-server/nats-server-v2.0.0-linux-amd64/nats-server /usr/bin
```

## Installing From the Source

If you have Go installed, installing the binary is easy:

```text
> GO111MODULE=on go get github.com/nats-io/nats-server/v2
```

This mechanism will install a build of [master](https://github.com/nats-io/nats-server), which almost certainly will not be a released version. If you are a developer and want to play with the latest, this is the easiest way.

To test your installation \(provided the $GOPATH/bin is set\):

```text
> nats-server
[41634] 2019/05/13 09:42:11.745919 [INF] Starting nats-server version 2.0.0
[41634] 2019/05/13 09:42:11.746240 [INF] Listening for client connections on 0.0.0.0:4222
...
[41634] 2019/05/13 09:42:11.746249 [INF] Server id is NBNYNR4ZNTH4N2UQKSAAKBAFLDV3PZO4OUYONSUIQASTQT7BT4ZF6WX7
[41634] 2019/05/13 09:42:11.746252 [INF] Server is ready
```

## NATS v2 and Go Modules

If you are having issues when using the recent versions of NATS and Go modules such as:

```text
go: github.com/nats-io/go-nats@v1.8.1: parsing go.mod: unexpected module path "github.com/nats-io/nats.go"
go: github.com/nats-io/go-nats-streaming@v0.5.0: parsing go.mod: unexpected module path "github.com/nats-io/stan.go"
```

To fix it:

1\) Update your `go.mod` using the latest tags, for example for both NATS and NATS Streaming clients:

```ruby
module github.com/wallyqs/hello-nats-go-mod

go 1.12

require (
    github.com/nats-io/nats.go v1.8.1
    github.com/nats-io/stan.go v0.5.0
)
```

Or if you want to import the NATS Server v2 to embed it, notice the `/v2` after the nats-server module name. If that is not present, then go modules will not fetch it and would accidentally end up with 1.4.1 version of the server.

```ruby
require (
    github.com/nats-io/nats-server/v2 v2.0.0
    github.com/nats-io/nats.go v1.8.1
)
```

If embedding both NATS Streaming and NATS Servers:

```ruby
require (
    github.com/nats-io/nats-server/v2 v2.0.0 // indirect
    github.com/nats-io/nats-streaming-server v0.15.1
)
```

2\) Next, update the imports within the repo:

```bash
find ./ -type f -name "*.go" -exec sed -i -e 's/github.com\/nats-io\/go-nats-streaming/github.com\/nats-io\/stan.go/g' {} \;

find ./ -type f -name "*.go" -exec sed -i -e 's/github.com\/nats-io\/go-nats/github.com\/nats-io\/nats.go/g' {} \;

find ./ -type f -name "*.go" -exec sed -i -e 's/github.com\/nats-io\/gnatsd/github.com\/nats-io\/nats-server\/v2/g' {} \;

find ./ -type f -name "*.go" -exec sed -i -e 's/github.com\/nats-io\/nats-server/github.com\/nats-io\/nats-server\/v2/g' {} \;
```

3\) \(Recommended\) Run Go fmt as the rename will affect the proper ordering of the imports

### Gotchas when using `go get`

When using `go get` to fetch the client, include an extra slash at the end of the repo. For example:

```text
GO111MODULE=on go get github.com/nats-io/nats.go/@latest
GO111MODULE=on go get github.com/nats-io/nats.go/@v1.8.1
```

When trying to fetch the latest version of the server with `go get`, you have to add `v2` at the end:

```text
GO111MODULE=on go get github.com/nats-io/nats-server/v2@latest
```

Otherwise, `go get` will fetch the `v1.4.1` version of the server, which is also named \(`gnatsd`\), the previous name for nats-server.

```text
GO111MODULE=on go get github.com/nats-io/nats-server@latest
go: finding github.com/nats-io/gnatsd/server latest
go: finding golang.org/x/crypto/bcrypt latest
go: finding golang.org/x/crypto latest
```

In order to use an older tag, you will have to use the previous name \(gnatsd\) otherwise it will result in `go mod` parsing errors.

```text
# OK
GO111MODULE=on go get github.com/nats-io/go-nats/@v1.7.2

# Not OK
GO111MODULE=on go get github.com/nats-io/nats.go/@v1.7.2
go: finding github.com/nats-io/nats.go v1.7.2
go: downloading github.com/nats-io/nats.go v1.7.2
go: extracting github.com/nats-io/nats.go v1.7.2
go: finding github.com/nats-io/go-nats/encoders/builtin latest
go: finding github.com/nats-io/go-nats/util latest
go: finding github.com/nats-io/go-nats/encoders latest
go: finding github.com/nats-io/go-nats v1.8.1
go: downloading github.com/nats-io/go-nats v1.8.1
go: extracting github.com/nats-io/go-nats v1.8.1
go: github.com/nats-io/go-nats@v1.8.1: parsing go.mod: unexpected module path "github.com/nats-io/nats.go"
go: error loading module requirements
```

For more information you can review the original issue in [GitHub](https://github.com/nats-io/nats.go/issues/478).