If the ArangoDB server does not start or if you cannot connect to it using arangosh or other clients, you can try to find the problem cause by executing the following steps. If the server starts up without problems you can skip this section.
Check the server log file: If the server has written a log file you should check it because it might contain relevant error context information.
Check the configuration: The server looks for a configuration file named arangod.conf on startup. The contents of this file will be used as a base configuration that can optionally be overridden with command-line configuration parameters. You should check the config file for the most relevant parameters such as:
- server.endpoint: What IP address and port to bind to
- log parameters: If and where to log
- database.directory: Path the database files are stored in
If the configuration reveals that something is not configured right the config file should be adjusted and the server be restarted.
Start the server manually and check its output: Starting the server might fail even before logging is activated so the server will not produce log output. This can happen if the server is configured to write the logs to a file that the server has no permissions on. In this case the server cannot log an error to the specified log file but will write a startup error on stderr instead. Starting the server manually will also allow you to override specific configuration options, e.g. to turn on/off file or screen logging etc.
Check the TCP port: If the server starts up but does not accept any incoming connections this might be due to firewall configuration between the server and any client(s). The server by default will listen on TCP port 8529. Please make sure this port is actually accessible by other clients if you plan to use ArangoDB in a network setup.
When using hostnames in the configuration or when connecting, please make sure the hostname is actually resolvable. Resolving hostnames might invoke DNS, which can be a source of errors on its own.
It is generally good advice to not use DNS when specifying the endpoints and connection addresses. Using IP addresses instead will rule out DNS as a source of errors. Another alternative is to use a hostname specified in the local /etc/hosts file, which will then bypass DNS.
Test if curl can connect: Once the server is started, you can quickly verify if it responds to requests at all. This check allows you to determine whether connection errors are client-specific or not. If at least one client can connect, it is likely that connection problems of other clients are not due to ArangoDB's configuration but due to client or in-between network configurations.
You can test connectivity using a simple command such as:
curl --dump - -X GET http://127.0.0.1:8529/_api/version && echo
This should return a response with an HTTP 200 status code when the server is running. If it does it also means the server is generally accepting connections. Alternative tools to check connectivity are lynx or ab.