compute-tools: Host Setup
=========================


1. Debian Packages
-------------------

apt install bridge-utils ifenslave vlan


2. Boot Parameters
------------------

2.1 CGroup Memory Controller
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

In order to enable the memory controller the following boot parameter needs to be used:

	cgroup_enable=memory


2.2 CGroup Swap Controller
~~~~~~~~~~~~~~~~~~~~~~~~~~

In order to enable the swap controller the following boot parameter needs to be used:

	swapaccount=1

2.3 vsyscall
~~~~~~~~~~~~

In order to be able to execute binaries linked to older libc versions
(<= wheezy) newer linux versions (>= buster), add the following boot parameter
(see #881813 for more information):

	vsyscall=emulate


3. Networking
~~~~~~~~~~~~~

3.1 Enable IPv4 Forwarding
~~~~~~~~~~~~~~~~~~~~~~~~~~

apt install procps
echo "net.ipv4.ip_forward = 1" > /etc/sysctl.d/ip_foward.conf
sysctl -p


3.2 Configure Network Bridge
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

3.2.1 Bridge: 1 Interface, standalone, DHCP
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

cat > /etc/network/interfaces << EOF
# /etc/network/interfaces

source /etc/network/interfaces.d/*

auto lo
iface lo inet loopback

iface eno1 inet manual

auto bridge0
iface bridge0 inet dhcp
	bridge_ports	eno1
	bridge_fd	0
	bridge_maxwait	0
	bridge_stp	0
EOF


3.2.2 Bridge: 1 Interface, standalone, static
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

cat > /etc/network/interfaces << EOF
# /etc/network/interfaces

source /etc/network/interfaces.d/*

auto lo
iface lo inet loopback

iface eno1 inet manual

auto bridge0
iface bridge0 inet static
	address		10.0.0.2
	gateway		10.0.0.1
	netmask		24

	pre-up		ip link set eno1 down
	pre-up		ip link set eno1 up

	bridge_ports	eno1
	bridge_fd	0
	bridge_maxwait	0
	bridge_stp	0
EOF


3.2.3 Bridge: 2 logical Interfaces, subnet, static
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

cat > /etc/network/interfaces << EOF
# /etc/network/interfaces

source /etc/network/interfaces.d/*

auto lo
iface lo inet loopback

allow-hotplug eno1
iface eno1 inet dhcp

auto bridge0
iface bridge0 inet static
	address		10.0.0.1
	netmask		24

	pre-up		ip link add name bridge0 type bridge
	post-down	ip link delete bridge0 type bridge

	bridge_fd	0
	bridge_maxwait	0
	bridge_stp	0
EOF


3.2.4 Bridge: 3 physical Interfaces, vlan, bonding, static
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

cat > /etc/network/interfaces << EOF
# /etc/network/interfaces

source /etc/network/interfaces.d/*

auto lo
iface lo inet loopback

allow-hotplug eno1
iface eno1 inet dhcp

iface eno2 inet manual

iface eno3 inet manual

auto bond0
iface bond0 inet manual
	up			ip link set bond0 up
	down			ip link set bond0 down

	slaves			eno2 eno3

	bond-mode		4
	bond-miimon		100
	bond-downdelay		200
	bond-updelay		200
	bond-lacp-rate		1
	bond-xmit-hash-policy	layer2+3

iface bond0.100 inet manual
	vlan-raw-device bond0

auto bridge-100
iface bridge-100 inet static
	address			10.100.0.2
	netmask			24

	bridge_ports		bond0.100
	bridge_fd		0
	bridge_maxwait		0
	bridge_stp		0
EOF


4. Enabling user namespace for unprivileged containers
------------------------------------------------------

Linux supports unprivileged containers with the user namespace.
By default the user namespace is disabled on Debian systems (see #898446).
To enable user namespace, edit the following file for a permant change:

  /etc/sysctl.d/zz-compute-tools.conf
  sysctl -p

or enable it manually with:

  echo 1 > /proc/sys/kernel/unprivileged_userns_clone

Note that containers need to be started with the correct
configuration in /etc/compute-tools/container/config to run unpriviled
(private-users option).


5. Enabling container-shell
---------------------------

Managing privileged containers requires root privileges. In order to allow
unprivileged users to manage privileged containers without granting them
privileges or accounts, the container-shell can be used together with sudo
and a container user.

  sudo adduser --gecos "compute-tools,,," \
	--home /var/lib/open-infrastructure/container-shell \
	--shell /usr/bin/container-shell


6. IPv4 and IPv6 dual-stack
---------------------------

Examples for /etc/network/interfaces above work for IPv6 too when using correct
IPv6 addresses and netmasks.

In order to use dual-stack, bridges must have a IPv4 address assigned
(can be a dummy one from a privacy range or 127.0.0.0/8).

Let me repeat: dual-stack only works when you assign a primary IPv6 address
(private or public, doesn't matter) *and* add an additional IPv4 address.
Yes, the IPv4 address can be a private address, the containers can still
have a public IPv4 address.

A complete example looks like this:

auto bridge0
iface bridge0 inet6 static
	address			2a07:6b47:4::4:1
	netmask			48

	up			ip addr add 127.4.4.1 dev $IFACE
	down			ip addr del 127.4.4.1 dev $IFACE

	bridge_fd		0
	bridge_maxwait		0
	bridge_stp		0
	bridge-mcquerier	1
