I recently installed a 5 node Datastax Enterprise/Cassandra 2.1 cluster on Ubuntu 14.04 using a Datastax AMI. I was able to bring the cluster up successfully, however when I did, I received errors on console about some linux limits, shown below:
The linux limit 'memlock' is '64'. The recommended is 'unlimited'.
Check your limits.conf. The linux limit 'nofile' is '4096'. The
recommended is '100000'. Check your limits.conf. Check our
documentation for more details. http://docs.datastax.com/en/cassandra/2.1/cassandra/install/installRecommendSettings.html?scroll=reference_ds_sxl_gf3_2k__user-resource-limits
When I checked the limits file, the memlock and nofile limits are set properly for both the cassandra and root user. However the settings are getting ignored. Has anyone else experienced this problem? I'm not that experienced with linux settings and I'm not sure where to look for an error. Sorry if this has already been asked and answered, I didn't find this question when searching.
Bob Glassett
You may want to try and reboot the systems. The package installer will try to use sysctl to set the various options at runtime, but maybe there was an issue with that.
Related
Suggest a solution if such exists.
There are 20 empty baremetal servers. Me need to go to the ipmi and manually connect the image file to start the installation OS.
Question: are there any solutions to automate this process?
Since you tag this question with "OpenStack", you must have heard of Ironic.
If the thought of installing OpenStack to automatically install servers frightens you, look up Cobbler. It was used by now defunct products Helion OpenStack and SUSE OpenStack Cloud to set up clouds.
Ubuntu uses MAAS for this purpose.
This is not a complete list.
I'm trying to access an exfat partition by windows 10 linux bash, but the partition doesn't show in the /mnt/ path. Only the NTFS partitions.
Already tried to install the libs exfat-fuse exfat-utils. Nothing happens.
Does anyone know how to make it work?
This is not currently supported. The issue is being tracked on Microsoft's github bug tracker here: https://github.com/Microsoft/BashOnWindows/issues/801 (currently unassigned and not committed to as of 25/08/2016)
NOTE: As of 27/07/2017 the issue linked above has been resolved and FAT (and exFAT) partitions should be mountable.
I think it is not supported yet...wait for full version, or you can write question to Microsoft developers
I would like to monitor and log the memory usage of processes being carried out by the different nodes in my ros-based system.
Ideally, the information would be similar to the output of the linux top command, but only for ros processes. The rqt_top plugin seems promising, but I am unclear about how to use/store information from this package.
Examples/tutorials for rqt_top or alternative ways to store memory usage data would be appreciated!
Using ros indigo and Ubuntu 14.04
Found an answer!
Jeet Sukumaran's Syrupy (https://github.com/jeetsukumaran/Syrupy) seems to solve my problem quite well and can be easily added to the launch of my ros nodes.
I have pretty strange problem with Collectd. I'm not new to Collectd, was using it for a long time on CentOS based boxes, but now we have Ubuntu TLS 12.04 boxes, and I have really strange issue.
So, using version 5.2 on Ubuntu 12.04 TLS. Two boxes residing on Rackspace (maybe important, but I'm not sure). Network plugin configured using two local IPs, without any firewall in between and without any security (just to try to set simple client server scenario).
On both servers collectd writes in configured folders as it should write, but on server machine it doesn't write data received from client.
Troubleshooted with tcpdump, and I can clearly see UDP traffic and collectd data, including hostname and plugin names from my client machine, received on server, but they are not flushed to appropriate folder (configured by collectd) ever. Also running everything as root user, to avoid troubleshooting permissions.
Anyone has any idea or similar experience with this? Or maybe some idea what could I do for troubleshooting this beside trying to crawl internet (I think I clicked on every sensible link Google gave me in last two days) and checking network layer (which looks fine)?
And just small note: exactly the same happened with official 4.10.2 version from Ubuntu's repo. After trying to troubleshoot it for hours moved to upgrade to version five.
I'd suggest trying out the quite generic troubleshooting procedure based on the csv and logfile plugins, as described in this answer. As everything seems to be fine locally, follow this procedure on the server, activating only the network plugin (in addition to logfile, csv and possibly rrdtool).
So after no way of fixing this, I upgraded my Ubuntu to 12.04.2 LTS (3.2.0-24-virtual) and this just started working fine, without any intervention.
I need to build a small cluster for my research. It's pretty humble and I'd like to build a cluster just with my other 3 laptops at home.
I'm writing in C++. My codes in MPI framework are ready. I can simulate them using visual studio 2010 and they're fine. Now I want to see the real thing.
I want to do it free (I'm a student). I have ubuntu installed and I wonder:
if I could build a cluster using ubuntu. I couldn't find a clear answer to that on the net.
if not, is there a free linux distro that I can use at building cluster?
I also wonder if I have to install ubuntu, or the linux distro on the host machine to all other laptops. Will any other linux distribution (like openSUSE) work with the one at the host machine? Or do all of them have to be same linux distro?
Thank you all.
In principle, any linux distro will work with the cluster, and also in principle, they can all be different distros. In practice, it'll be a enormously easier with everything the same, and if you get a distribution which already has a lot of your tools set up for you, it'll go much more quickly.
To get started, something like the Bootable Cluster CD should be fairly easy -- I've not used it myself yet, but know some who have. It'll let you boot up a small cluster without overwriting anything on the host computer, which lets you get started very easily. Other distributions of software for clusters include Rocks and Oscar. A technical discussion on building a cluster can be found here.
I also liked PelicanHPC when I used it a few years back. I was more successful getting it to work that with Rocks, but it is much less popular.
http://pareto.uab.es/mcreel/PelicanHPC/
Just to get a cluster up and running is actually not very difficult for the situation you're describing. Getting everything installed and configured just how you want it though can be quite challenging. Good luck!