install mongodb-2.6.12 from the tarball

install-mongodb-2.6.12-from-tarball.sh

#!/usr/bin/env bash
# run this script from your home folder
# sudo bash
curl -O http://downloads.mongodb.org/linux/mongodb-linux-x86_64-2.6.12.tgz

tar -zxvf mongodb-linux-x86_64-2.6.12.tgz
cp mongodb-linux-x86_64-2.6.12/bin/* /usr/local/bin
groupadd mongodb
useradd --system --no-create-home -g mongodb mongodb

mkdir -p /var/log/mongodb
touch /var/log/mongodb/mongodb.log

mkdir -p /var/lib/mongodb/

chown mongodb:mongodb -R /var/lib/mongodb
chown mongodb:mongodb -R /var/log/mongodb

cat > /etc/mongod.conf <<EOF
dbpath=/var/lib/mongodb
logpath=/var/log/mongodb/mongodb.log
logappend=true
EOF

cat > /etc/systemd/system/mongodb.service <<EOF
[Unit]
Description=High-performance, schema-free document-oriented database
After=network.target

[Service]
User=mongodb
ExecStart=/usr/local/bin/mongod --config /etc/mongod.conf

[Install]
WantedBy=multi-user.target
EOF

systemctl daemon-reload
systemctl restart mongodb.service
systemctl status mongodb.service

mongod.conf

# mongod.conf

#where to log
logpath=/var/log/mongodb/mongodb.log

logappend=true

# fork and run in background
#fork=true

#port=27017

dbpath=/var/lib/mongodb

# location of pidfile
#pidfilepath=/var/run/mongodb/mongod.pid

# Listen to local interface only. Comment out to listen on all interfaces. 
#bind_ip=127.0.0.1

# Disables write-ahead journaling
# nojournal=true

# Enables periodic logging of CPU utilization and I/O wait
#cpu=true

# Turn on/off security.  Off is currently the default
#noauth=true
#auth=true

# Verbose logging output.
#verbose=true

# Inspect all client data for validity on receipt (useful for
# developing drivers)
#objcheck=true

# Enable db quota management
#quota=true

# Set oplogging level where n is
#   0=off (default)
#   1=W
#   2=R
#   3=both
#   7=W+some reads
#diaglog=0

# Ignore query hints
#nohints=true

# Enable the HTTP interface (Defaults to port 28017).
#httpinterface=true

# Turns off server-side scripting.  This will result in greatly limited
# functionality
#noscripting=true

# Turns off table scans.  Any query that would do a table scan fails.
#notablescan=true

# Disable data file preallocation.
#noprealloc=true

# Specify .ns file size for new databases.
# nssize=<size>

# Replication Options

# in replicated mongo databases, specify the replica set name here
#replSet=setname
# maximum size in megabytes for replication operation log
#oplogSize=1024
# path to a key file storing authentication info for connections
# between replica set members
#keyFile=/path/to/keyfile