mongodb connection issue: `connect’: Failed to connect to a master node at localhost:27017 (Mongo::ConnectionFailure)

You just try to start the mongodb by

service mongod start


start mongod

And check mongodb process is running by checking

ps aux | grep mongo

You can see the status by

service mongod status

If it is not starting then try to remove the mongod lock file by,

rm /var/lib/mongodb/mongod.lock

Then start the mongodb server again.


Install RVM, Ruby on CentOS

First download the Ruby Version Manager (RVM) installer as follows

$ sudo bash -s stable < <(curl -s )

RVM requires to add relevant users to it’s group. Open the file like so:

$ sudo vim /etc/group

Edit the ‘rvm’ group (likely the last entry) to look like:

Run the install:

$ cd /usr/local/rvm/bin
$ sudo ./rvm-installer

“Upgrade of RVM in /usr/local/rvm/ is complete.”

I needed to reload the RVM to continue, this might not be required:

$ rvm reload

If it shows -bash: rvm: command not found

please close the terminal and start it again to load the RVM.

Now we can install the Ruby version. This will also install rubygems which is always useful…

$ rvm install 1.9.3 --with-openssl-dir=/usr
$ ruby -v
$ rvm use ruby-1.9.3-p327 --default

If you are getting nokogiri error like:

Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.

checking for libxslt/xslt.h… no

libxslt is missing.

then install

$ sudo yum install -y gcc ruby-devel libxml2 libxml2-devel libxslt libxslt-devel


Remove and reset jQuery token input drop down values through ajax

If you have a requirement for reloading the token input drop down values, you can remove the token input by


and add token input to the selector by

                {id: 7, name: "Ruby"},
                {id: 41, name: "C"},
                {id: 43, name: "C++"},
                {id: 47, name: "Java"}
            ], {
      propertyToSearch: "name",
      theme: "facebook",
      preventDuplicates: true});