[systemd] Add value to LimitNOFILE due to performance problems

Fixes #1729: Use 'is changed' instead of non-existent changed filter.

When k3s is installed on an OS with default high ulimits, performance
issues can be observed. This was discovered on CoreOS where the default
value is 1073741816. Symptoms include very slow file operations such
as installing a Rook/Ceph cluster will take ~6 hours instead of ~10 minutes.

A google search for 'container LimitNOFILE' will show that most major
projects set this already, including the (unused) containerd systemd unit
found in this repository at /vendor/github.com/containerd/containerd/containerd.service

k3OS is not affected becuasse the default there is already 1048576.

See description in coreos/fedora-coreos-tracker#329

Signed-off-by: Julien DOCHE <julien.doche@gmail.com>

There are some issues and quirks in the markdown documentation files
suggested by the markdownlint project checker that might benefit from
being fixed, which this patch does.

Change-Id: I33245825e5bb543b5ce1732204984d4a0b169668
Signed-off-by: Joakim Roubert <joakimr@axis.com>

contrib/ansible: Fix home path and use kubectl to set the server url in conf

Signed-off-by: Julien DOCHE <julien.doche@gmail.com>

Sometimes https://127.0.0.1:6443

 can be written in the conf, the regexp does
not account for that.

Signed-off-by: Julien DOCHE <julien.doche@gmail.com>

Signed-off-by: Julien DOCHE <julien.doche@gmail.com>

Signed-off-by: Julien DOCHE <julien.doche@gmail.com>

- Setting IPv4 & IPv6 forwarding
- Setting `sysctl:net.bridge.bridge-nf-call-iptables` and `bridge-nf-call-ip6tables` to enabled since it is disabled by default on some CentOS systems

Add a little extra delay between restart attempts

The example inventory uses the group `kube-cluster`, but the playbooks references `k3s-cluster`. This resolves the inconsistency.

Ansible: Test for Raspbian before assuming

contrib/ansible: Allow 'server' and 'node' roles to co-exist on a single host

Ansible - fix typo and add kubeconfig copy to user homedir

Ansible provisionning contrib