DataStax OpsCenter Documentation


This section lists some common problems experienced with OpsCenter and solutions or workarounds.

Internet Explorer browser is not supported

If you try to load the OpsCenter client in Microsoft Internet Explorer, a dialog displays informing you that it is not supported.

OpsCenter is only supported on the latest versions of:

  • Mozilla Firefox
  • Google Chrome
  • Apple Safari


General Troubleshooting Steps

  • Ensure firewalls are properly opened between the opscenterd machine and each node.
  • Check the following files (on any of the nodes having problems) for any errors:
    • /var/log/cassandra/system.log
    • /var/log/opscenter-agent/agent.log
  • Verify that Cassandra (or DSE) was not previously installed on any of the machines; if it was, all binaries, configuration files, logs, etc. must be cleared out first.

Invalid Repository Credentials


When installing DSE, if you enter invalid values for DataStax Credentials, an error dialog displays text along the lines of:

Installation stage failed: Installation failed on node 'apt-get update' failed.

Clicking Details displays the entire output from both stdout and stderr. If, in this output, you see the "401 Unauthorized", it means that the credentials entered were invalid.


When installing DSE, if you enter invalid values for DataStax Credentials, an error dialog displays text along the lines of:

Installation failed on node 'yum install' failed.

Clicking Details displays the entire output from both stdout and stderr. If, in this output, you see "The requested URL returned error: 401", it means that the credentials used were invalid.

Timed out waiting for Cassandra to start

If you receive this error, it most likely means that the Cassandra process failed to start on one or more nodes. You should look in /var/log/cassandra/system.log for any errors that may need to be resolved.

The following packages are already installed

If you receive an error that starts with this message, it means Cassandra (or DSE) is already installed on the system. OpsCenter provisioning requires that any instances of Cassandra (or DSE) be completely removed or purged before provisioning a new cluster.

Agents cannot connect to opscenterd

If you receive an error message that includes "The installed agent doesn't seem to be responding", there is most likely a firewall issue preventing the installed agent from connecting to the opscenterd machine. You should ensure that port 61620 is open on the opscenterd machine and check the agent logs.

Cannot create a keyspace

Due to a Python 2.6 or earlier bug, some users experience a problem adding a keyspace using Data Modeling OpsCenter features. OpsCenter cannot save a newly created keyspace.

Upgrading Python generally fixes this problem.

Error displayed

Your CentOS 5.x, Debian, OEL 5.5, RHEL 5.x, or Ubuntu operating system has OpenSSL 1.0.0 installed and you see an error containing this message.


To correct this situation, install OpenSSL 0.9.8.

  • To install OpenSSL 0.9.8 on OEL and RHEL, run sudo yum install openssl098.
  • To install OpenSSL 0.9.8 on CentOS, Debian, or Ubuntu, run sudo apt-get install libssl0.9.8.

Python used to run OpsCenter not built with SSL

In order to protect your AWS credentials when launching EC2 instances, OpsCenter needs to use HTTPS, but if the version of Python that is running opscenterd was not compiled with SSL support OpsCenter will not run even if SSL has been disabled in the configuration file.

To resolve the issue, first ensure that OpenSSL 0.9.8 is installed on your system. If you have compiled Python manually, it is recommended that you install Python 2.6+ through your package manager. On CentOS and RedHat Enterprise Linux, this is most easily done through EPEL packages.

If you must compile Python manually, make sure that SSL support is enabled. This blog post explains the process for Python 2.5, but the same steps will work for Python 2.6 or 2.7.

OpsCenter agent port setting conflict

If you have a problem with OpsCenter, check for conflicts in port settings. The OpsCenter Agent uses port 7199 by default. If you have not changed the default port, check that Cassandra or another process on the node, is not set up to use this port.

If you set the OpsCenter Agent port to a host name instead of an IP address, the DNS provider must be online to resolve the host name. If the DNS provider is not online, intermittent problems should be expected.

Limiting the metrics collected by OpsCenter

If you have many column families, the number of metrics OpsCenter collects can become quite large. For information about how to reduce the number keyspaces or column families that are monitored, see Controlling data collection.

Java not installed or JAVA_HOME environment variable not set

If Java is not installed or if OpsCenter cannot find JAVA_HOME, you may see an error such as:

/usr/share/opscenter-agent/bin/opscenter-agent: line 98: exec: -X: invalid option
exec: usage: exec [-cl] [-a name] [command [arguments ...]] [redirection ...]

To correct this problem, install Java or set JAVA_HOME:

export JAVA_HOME=<path_to_java>

Insufficient user resource limits errors

Insufficient resource limits may result in an insufficient nofiles error:

2012-08-13 11:22:51-0400 [] INFO: Could not accept new connection (EMFILE)

See Recommended settings under Insufficient user resource limits errors in the Cassandra documentation.