Host Setup Common Issues
This section describes some common issues that may prevent NXLog Manager from working correctly. These are not related to the installation or configuration of the Manager itself.
For NXLog Manager to work correctly, the hostname of the host must
resolve to the correct IP address. The following error will be present
/opt/nxlog-manager/log/nxlog-manager.err, if that is not the case.
2016-11-21 16:14:31,015 ERROR manager-host unknown nxlog-manager [net.sf.ehcache.Cache] - Unable to set manager-host. This prevents creation of a GUID. Cause was: java.net.UnknownHostException: nxlogmgr.domain.local
To set the hostname to myname, the line containing the host IP
address along with the FQDN and the name aliases should be added to the
172.16.183.1 myname.example.com myname
Any of the locally bound IP address may be used as the Manager hostname.
/etc/hosts file works for both Debian and RHEL versions of
By default, a Docker container inherits DNS settings from the Docker daemon,
including the contents of the
These settings can be overridden on a per-container basis with the following
The IP address of a DNS server. Multiple
A key-value pair representing a DNS option and its value. See the operating
system’s documentation for the
The hostname a container uses for itself. Defaults to the container’s ID if not specified.
Make sure that your DNS is setup correctly and it is functioning properly. DNS timeouts and errors can cause various issues, mainly because TLS certificate verification is using DNS lookups.
|It is important to understand, that there is no single method of getting a DNS lookup configuration done on Linux.|
The most common way is to edit the
/etc/resolv.conf file. Usually up to
three nameservers can be set up using the nameserver keyword, followed by the
IP address of the nameserver.
To test whether your configuration functions correctly, use the host or dig programs to perform both a DNS lookup and a reverse DNS lookup (by querying with an IP address). Make sure that participating hosts on your NXLog collection system are resolved correctly.
For more information, visit the Manually configuring the /etc/resolv.conf file in the RedHat documentation for RHEL related distributions or visit the Defining the (DNS) Nameservers section in the Debian Wiki for Debian based distrubutions.
There is also a comprehensive article on the Anatomy of a Linux DNS Lookup on the zwischenzugs website that discusses the different methods and tools that can be used.