installing varnish in ubuntu 16.04

Question

Tried with 2 different approaches to setup varnish on ubuntu 16.04 in azure but not sure whether the approach of installation is correct.

Referred with different websites all seems to be same set of commands.

Approach 1

sudo apt-get update
sudo apt-get upgrade
sudo apt-get install varnish

.........
.........
Setting up libvarnishapi1 (4.1.1-1ubuntu0.2) ...
Setting up manpages-dev (4.04-2) ...
Setting up libjemalloc1 (3.6.0-9ubuntu1) ...
Setting up varnish (4.1.1-1ubuntu0.2) ...
sent invalidate(passwd) request, exiting
sent invalidate(group) request, exiting
sent invalidate(passwd) request, exiting
sent invalidate(group) request, exiting
sent invalidate(group) request, exiting
sent invalidate(group) request, exiting
sent invalidate(passwd) request, exiting
sent invalidate(group) request, exiting
sent invalidate(passwd) request, exiting
sent invalidate(group) request, exiting
sent invalidate(passwd) request, exiting
sent invalidate(group) request, exiting
sent invalidate(passwd) request, exiting
sent invalidate(group) request, exiting
sent invalidate(passwd) request, exiting
sent invalidate(group) request, exiting
sent invalidate(passwd) request, exiting
sent invalidate(group) request, exiting
sent invalidate(passwd) request, exiting
sent invalidate(group) request, exiting
sent invalidate(passwd) request, exiting
sent invalidate(group) request, exiting
sent invalidate(passwd) request, exiting
sent invalidate(group) request, exiting
sent invalidate(passwd) request, exiting
sent invalidate(group) request, exiting
sent invalidate(passwd) request, exiting
sent invalidate(group) request, exiting
sent invalidate(passwd) request, exiting
sent invalidate(group) request, exiting
sent invalidate(passwd) request, exiting
sent invalidate(group) request, exiting
sent invalidate(passwd) request, exiting
sent invalidate(group) request, exiting
sent invalidate(passwd) request, exiting
sent invalidate(group) request, exiting
sent invalidate(passwd) request, exiting
sent invalidate(group) request, exiting
sent invalidate(passwd) request, exiting
sent invalidate(group) request, exiting
sent invalidate(passwd) request, exiting
sent invalidate(group) request, exiting
sent invalidate(passwd) request, exiting
sent invalidate(group) request, exiting
sent invalidate(passwd) request, exiting
sent invalidate(group) request, exiting
Processing triggers for libc-bin (2.23-0ubuntu9) ...
Processing triggers for systemd (229-4ubuntu21) ...
Processing triggers for ureadahead (0.100.0-19) ...

Is the above installation is correct since it gives sent invalidate.

Approach 2

sudo curl http://repo.varnish-cache.org/debian/GPG-key.txt | sudo apt-key add -
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   580  100   580    0     0   1172      0 --:--:-- --:--:-- --:--:--  1171
gpg: no valid OpenPGP data found.


sudo echo "deb http://repo.varnish-cache.org/ubuntu/ precise varnish-3.0" | sudo tee -a /etc/apt/sources.list

sudo apt-get update

Doing a update will result in below error.

W: The repository 'http://repo.varnish-cache.org/ubuntu precise Release' does not have a Release file.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: Failed to fetch http://repo.varnish-cache.org/ubuntu/dists/precise/varnish-3.0/binary-amd64/Packages  410  repo [IP: 176.58.90.154 80]
E: Some index files failed to download. They have been ignored, or old ones used instead.

Not sure both the approaches are correct as both are giving some errors.

Answer 1

Is the above installation is correct since it gives sent invalidate.

It's a known issue about Ubuntu 16.04.

When we try to add user to Ubuntu 16.04, we will get this error message, like this:

root@ubuntu:~# adduser test
Adding user `test' ...
sent invalidate(passwd) request, exiting
sent invalidate(group) request, exiting
Adding new group `test' (1001) ...
sent invalidate(passwd) request, exiting
sent invalidate(group) request, exiting
sent invalidate(group) request, exiting
sent invalidate(passwd) request, exiting
sent invalidate(group) request, exiting
Adding new user `test' (1001) with group `test' ...
sent invalidate(passwd) request, exiting
sent invalidate(group) request, exiting
sent invalidate(passwd) request, exiting
sent invalidate(group) request, exiting
sent invalidate(passwd) request, exiting
sent invalidate(group) request, exiting
Creating home directory `/home/test' ...
Copying files from `/etc/skel' ...
Enter new UNIX password: 
Retype new UNIX password: 
passwd: password updated successfully
Changing the user information for test
Enter the new value, or press ENTER for the default
    Full Name []: 
    Room Number []: 

As far as I know, the error message will not effect it.

jason@ubuntu:~$ su - test
Password: 
test@ubuntu:~$ 

Here the link about this issue, please refer to it.

Answer 2

You may refer "How to install Varnish on Ubuntu Server 16.04".