add key

curl -sL https://repos.influxdata.com/influxdb.key | sudo apt-key add -

add sources

echo "deb https://repos.influxdata.com/ubuntu trusty stable" | sudo tee /etc/apt/sources.list.d/influxdb.list

update

apt update

install

lwk@qwfys ~ $ apt install telegraf

start

sudo service telegraf start