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SETUP » История » Версия 5

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Владимир Ипатов, 24.10.2012 09:11

SETUP

Ensure both nodes are up.

If you planning to use the secondary network for SAN and DRBD synchronization, you
should configure secondary IP interfaces manually on both nodes at this time.

Log in to the first node via ssh. Due to lack of DNS there may be
a minute timeout before password prompt.

NETWORK CONFIGURATION

Network configuration may be highly various.
Here we describe several schemas.

Default schema

one ethernet, one subnet, internet connection provided by external (not in claster) router.
By default installer create bridge named xen-br0. You can customize parameters by editing /etc/network/interfaces.
By default it looks like:

auto xen-br0
iface xen-br0 inet static
        address 192.168.5.88
        netmask 255.255.255.0
        network 192.168.5.0
        broadcast 192.168.5.255
        gateway 192.168.5.1
        bridge_ports eth0
        bridge_stp off
        bridge_fd 0
#       up ifconfig eth0 mtu 9000
#       up ifconfig xen-br0 mtu 9000

Important parameters besides ipv4 settings is:
bridge_ports eth0 - means that physical interface eth0 enslaved to this bridge.

up ifconfig eth0 mtu 9000
up ifconfig xen-br0 mtu 9000 - setting jumbo frame on bridge for more net speed and less cpu utilization.
It will be actual on interface where drbd link will be.
However, setting mtu higher than 1500 will cause problems with any network equipment that
doesn't support jumbo frames. That's the reason because it option commented out by default.

Also it is important to specify broadcast and network adresses - it will help automatically
fullfill /etc/ganeti/networks file(a file that specify networks for instances).
However, it ins't required.

Mupltiple bridges with routing

Here is a bit more complicated network setup.
In this setup we have, for example, two private netwokrs and wan by ethernet. All routing and firewalling
performed by instance in our cluster. This setup fit when you don't have expensive hardware routers and firewalls.
This is /etc/network/interfaces file in this setup:

auto lan
iface lan inet static
    address 192.168.21.10
    netmask 255.255.255.0
        bridge_ports eth0
        bridge_stp off
        bridge_fd 0

auto dmz
iface dmz inet static
    address 192.168.20.10
    netmask 255.255.255.0
    gateway 192.168.20.1
        bridge_ports eth1
        bridge_stp off
        bridge_fd 0
        up ifconfig eth1 mtu 9000
        up ifconfig dmz mtu 9000

auto wan1
iface wan1 inet manual
        bridge_ports eth2
        bridge_stp off
        bridge_fd 0

In this example we have separate lan interfaces, dmz interface(it isn't actually dmz,
it just named this) and wan interface. dmz interface - ganeti master dev and drbd link
interfase, so there is mtu 9000.
There is no address in wan for hypervisor, although we recommend you to get subnet from
your ISP in order to assign IP addresses to nodes to management it even if router instance
is down.

Here is an example /etc/network/interfaces in router instance:

auto eth0
iface eth0 inet static
   address 192.168.20.1
   netmask 255.255.255.0

auto eth1
iface eth1 inet static
   address 192.168.21.1
   netmask 255.255.255.0

auto eth2
iface eth2 inet static
   address 1.1.1.2
   netmask 255.255.255.0
   address 1.1.1.1

Where eth0 linked to bridge dmz, eth1 linked to lan, eth2 linked to wan.

VLAN schema

If you have managed switches, you can set networking with VLANs.
You should add something like this for each VLAN:

auto eth0.55
iface eth0.55 inet manual
        up ifconfig eth0.55 up

auto bridge-example-vlan
iface bridge-example-vlan inet manual
        up brctl addbr bridge-example-vlan
        up brctl addif bridge-example-vlan eth0.55
        up brctl stp bridge-example-vlan off
        up ifconfig bridge-example-vlan up
        down ifconfig bridge-example-vlan down
        down brctl delbr bridge-example-vlan

Where 55 - VLAN number.
In this example node don't have an ip address in this VLAN, although you could
assign an ip to bridge just like standard bridge.

Alternative schema is:

auto vlan55
iface vlan55 inet manual
   vlan_raw_device eth0

auto bridge-example-vlan
iface bridge-example-vlan inet manual
           bridge_ports vlan55
        bridge_stp off
        bridge_fd 0

It do the same, but in another way.

DEFINING ENVIRONMENT

Edit /etc/sci/sci.conf

  • You should specify node1 and node2 data as you have installed them.
    NOTE: You can setup the cluster even with one node. In this case just leave NODE2_
    lines as is. In fact this is a dangerous setup, so you will be warned about this duging
    the procedures.
  • You should specify the cluster's name and IP.
  • NODE#_SAN_IP should be specified on both nodes or none.
  • If you haven't Internet uplink or have a local package mirrors, you should correct
    APT_ - settings.
  • If you need to uplink to the DNS hierarchy other than root hint zones, specify DNS_FORWARDERS
    (note trailing ';').

SETUP CLUSTER

Issue:

# sci-setup cluster

Check and confirm settings printed.

The process will go on.

Next you will be prompted to accept ssh key from node2 and for the root's password to node2.

On finish you will look something like this:

Verify
Wed Jan 12 15:36:10 2011 * Verifying global settings
Wed Jan 12 15:36:10 2011 * Gathering data (1 nodes)
Wed Jan 12 15:36:11 2011 * Verifying node status
Wed Jan 12 15:36:11 2011 * Verifying instance status
Wed Jan 12 15:36:11 2011 * Verifying orphan volumes
Wed Jan 12 15:36:11 2011 * Verifying orphan instances
Wed Jan 12 15:36:11 2011 * Verifying N+1 Memory redundancy
Wed Jan 12 15:36:11 2011 * Other Notes
Wed Jan 12 15:36:11 2011 * Hooks Results
Node                    DTotal  DFree MTotal MNode MFree Pinst Sinst
gnt1.ganeti.example.org 100.0G 100.0G  1020M  379M  625M     0     0
gnt2.ganeti.example.org 100.0G 100.0G  1020M  379M  625M     0     0
If all is ok, proceed with /usr/local/sbin/sci-setup service

SETUP SERVICE INSTANCE

The service instance is named 'sci' and have a few aliases.
On setup, it's IP address is determined from /etc/resolv.conf of your first node.
This instance will be hardcoded in /etc/hosts file of all cluster nodes and instances.

Issue:

# sci-setup service

You'll see the progress of DRBD syncing disks, then the message

* running the instance OS create scripts...

appears. The further may take a while. The process finishes with
* starting instance...

message.

Now you can log on to the sci instance using:

# gnt-instance console sci

Log in as root, the password is empty.
NOTE: Due to empty password all remote connections to new instance is prohibited.
You should change password and install openssh-server package manually after
successful bootstrap procedure.

SERVICE INSTANCE BOOTSTRAP

The system will setup itself via puppet. This is the iterative process. You can monitor
it by looking into /var/log/daemon.log. At start there is no less command yet, so
you can use more, cat, tail or tail -f until less will be auto-installed.

By default the iterations are repeated in 20 minutes. To shorten the wait time you can
issue

# /etc/init.d/puppet restart

and then look into daemon.log how it finishes.

Repeat this a few times until puppet will do nothing in turn.

PREPARING FOR NEW INSTANCES

New instances are created just by regular Ganeti commands such as:

gnt-instance add -t drbd -o debootstrap+default -s 10g -B memory=256m -n NODE1_NAME:NODE2_NAME INSTANCE_NAME
Altought, some tuning hooks are provided by SCI-CD project:
  1. Each instance has installed puppet for autoconfiguration and openssh-client for file transfers etc.
  2. The instance uses pygrub to boot kernel from /vmlinuz & Co on the innstance's own disk.
  3. The instance's network interfaces may be set up automatically as described below.

INSTANCE INTERFACE AUTOCONFIGURATION

If your instances may sit on several networks and you need static addressing in them, you should fulfill
the file /etc/ganeti/networks with all known networks you want to attach your instances.
Each line in the file has format

NETWORK NETMASK BROADCAST GATEWAY

Ganeti instance debootstrap hook looks in this file for the network, mathing the address of bootstraped
instance and fulfill it's /etc/network/interfaces accordingly.

NOTE: If you have only one default network, you shouldn't care because it's data are preinstalled.
NOTE: networks file must be copied to all cluster nodes (not automated yet).

SCI OPERATIONS

Read OPERATIONS next.