# Logging

## Logging with the systemd journal (CentOS, Amazon AMI, Ubuntu, Debian)

On distributions with systemd, ScyllaDB logs are written to the [systemd journal](http://www.freedesktop.org/software/systemd/man/systemd-journald.service.html). You can retrieve log entries with the [journalctl](http://www.freedesktop.org/software/systemd/man/journalctl.html) command.

Listed below are a few useful examples.

* get logs generated by the “scylla” user:
  ```shell
  journalctl _UID=`id -u scylla`
  ```
* get logs generated by the “scylla” command:
  ```shell
  journalctl _COMM=scylla
  ```
* filter only ScyllaDB logs by priority:
  ```shell
  journalctl _COMM=scylla -p err..emerg
  ```

  ```shell
  journalctl _COMM=scylla -p warning
  ```
* filter only ScyllaDB logs by date:
  ```shell
  journalctl _COMM=scylla --since="2013-3-16 23:59:59"
  ```

  ```shell
  journalctl _COMM=scylla --since "2015-01-10" --until "2015-01-11 03:00"`
  ```

  ```shell
  journalctl _COMM=scylla --since yesterday
  ```
* filter only ScyllaDB logs since last server boot:
  ```shell
  journalctl _COMM=scylla -b
  ```

## Logging on Ubuntu 14.04

On Ubuntu 14.04, ScyllaDB writes its initial boot message into `/var/log/upstart/scylla-server.log`.

After ScyllaDB has started, logs are stored in `/var/log/syslog`. ScyllaDB logs can be filter by creating a `rsyslog` configuration file with the following rule (for example, in `/etc/rsyslog.d/10-scylla.conf`)

```shell
:syslogtag, startswith, "scylla" /var/log/scylla/scylla.log
& ~
```

And then creating the log file with the correct permissions and restarting the service:

```shell
install -o syslog -g adm -m 0640 /dev/null /var/log/scylla/scylla.log
service rsyslog restart
```

This will send ScyllaDB only logs to `/var/log/scylla/scylla.log`

## Logging on Docker

Starting from ScyllaDB 1.3, [ScyllaDB Docker](https://hub.docker.com/r/scylladb/scylla/), you should use `docker logs` command to access ScyllaDB server logs.

[Getting Started](https://docs.scylladb.com/manual/master/getting-started/index.md)