dokku/docs/getting-started/troubleshooting.md

# Troubleshooting

__Symptom:__ I deployed my app but I am getting the default nginx page

__Solution:__

Most of the time it's caused by some defaults newer versions of nginx set. To make sure that's the issue you're having run the following:

```shell
nginx -t
## nginx: [emerg] could not build the server_names_hash, you should increase server_names_hash_bucket_size: 32
```

If you get a similar error just edit __/etc/nginx/nginx.conf__ and add the following line to your http section:

```nginx
http {
    (... existing content ...)
    server_names_hash_bucket_size 64;
    (...)
}
```

Note that the `server_names_hash_bucket_size` setting defines the maximum domain name length.
A value of 64 would allow domains with up to 64 characters. Set it to 128 if you need longer ones.

Save the file and try stopping nginx and starting it again:

```shell
/etc/init.d/nginx stop
## * Stopping nginx nginx                                        [ OK ]
/etc/init.d/nginx start
## * Starting nginx nginx                                        [ OK ]
```

***

__Symptom:__ I want to deploy my app, but while pushing I get the following error

    ! [remote rejected] master -> master (pre-receive hook declined)

__Solution:__

The `remote rejected` error does not give enough information. Anything could have failed.

To enable Dokku tracing, simply run the following command:

```shell
# since 0.3.9
dokku trace on
```

In versions older than 0.3.9, you can create a `/home/dokku/dokkurc` file containing the following :

```shell
export DOKKU_TRACE=1
```

This will trace all of dokku's activity. If this does not help you, create a [gist](https://gist.github.com) containing the full log, and create an issue.

***

__Symptom:__ I get the aforementioned error in the build phase (after turning on Dokku tracing)

  Most errors that happen in this phase are due to transient network issues (either locally or remotely) buildpack bugs.

__Solution (Less solution, more helpful troubleshooting steps):__

  Find the failed phase's container image (*077581956a92* in this example)

```shell
docker ps -a  | grep build
## 94d9515e6d93        077581956a92                "/build"       29 minutes ago      Exited (0) 25 minutes ago                       cocky_bell
```

  Start a new container with the failed image and poke around (i.e. ensure you can access the internet from within the container or attempt the failed command, if known)

```shell
docker run -ti 077581956a92 /bin/bash
curl -s -S icanhazip.com
## 192.168.0.1
curl http://s3pository.heroku.com/node/v0.10.30/node-v0.10.30-linux-x64.tar.gz -o node-v0.10.30-linux-x64.tar.gz
tar tzf node-v0.10.30-linux-x64.tar.gz
## ...
```

  Sometimes (especially on DO) deploying again seems to get past these seemingly transient issues
  Additionally we've seen issues if changing networks that have different DNS resolvers. In this case, you can run the following to update your resolv.conf

```shell
resolvconf -u
```

Please see https://github.com/dokku/dokku/issues/841 and https://github.com/dokku/dokku/issues/649

***

__Symptom:__ I want to deploy my app but I am getting asked for the password of the git user and the error message

    fatal: 'NAME' does not appear to be a git repository
    fatal: Could not read from remote repository.

__Solution:__

You get asked for a password because your ssh secret key can't be found. This may happen if the private key corresponding to the public key you added with `sshcommand acl-add` is not located in the default location `~/.ssh/id_rsa`.

You have to point ssh to the correct secret key for your domain name. Add the following to your `~/.ssh/config`:

```ini
Host DOKKU_HOSTNAME
  IdentityFile "~/.ssh/KEYNAME"
```

Also see [issue #116](https://github.com/dokku/dokku/issues/116)

***

__Symptom:__ I successfully deployed my application with no deployment errors and receiving Bad Gateway when attempting to access the application

__Solution:__

In many cases the application will require the a `process.env.PORT` port opposed to a specified port.

When specifying your port you may want to use something similar to:

```javascript
var port = process.env.PORT || 3000
```

Please see https://github.com/dokku/dokku/issues/282

***

__Symptom:__ Deployment fails because of slow internet connection, messages shows `gzip: stdin: unexpected end of file`

__Solution:__

If you see output similar this when deploying:

```
 Command: 'set -o pipefail; curl --fail --retry 3 --retry-delay 1 --connect-timeout 3 --max-time 30 https://s3-external-1.amazonaws.com/heroku-buildpack-ruby/ruby-2.0.0-p451-default-cache.tgz -s -o - | tar zxf -' failed unexpectedly:
 !
 !     gzip: stdin: unexpected end of file
 !     tar: Unexpected EOF in archive
 !     tar: Unexpected EOF in archive
 !     tar: Error is not recoverable: exiting now
```

it might that the curl command that is supposed to fetch the buildpack (anything in the low megabyte file size range) takes too long to finish, due to slowish connection.  To overwrite the default values (connection timeout: 3 seconds, total maximum time for operation: 30 seconds), set the following environment variables:

```shell
dokku config:set --global CURL_TIMEOUT=600
dokku config:set --global CURL_CONNECT_TIMEOUT=30
```

Please see https://github.com/dokku/dokku/issues/509