There are several commands that help in managing the instances. Here are a few examples:

$ euca-run-instances ami-00000003 -k mykey -t m1.tiny

RESERVATION	r-f1ek1ojb	proj	default
INSTANCE	i-00000005	ami-00000003			pending	mykey (proj, None)	0		m1.tiny	2011-10-19T12:48:04Z	unknown zone	ami-00000000	ami-00000000
$ euca-describe-instances

RESERVATION	r-f1ek1ojb	proj	default
INSTANCE	i-00000005	ami-00000003	192.168.4.3	192.168.4.3	running	mykey (proj, Openstackvalidationserver1)	0		m1.tiny	2011-10-19T12:48:04Z	nova	ami-00000000	ami-00000000
$ euca-reboot-instances i-00000005
$ euca-terminate-instances i-00000005
$ euca-run-instances ami-XXXXXXXX -k mykey
$ euca-get-console-output i-00000005

i-00000005
2011-10-07T07:22:40.795Z
[    0.000000] Initializing cgroup subsys cpuset
[    0.000000] Initializing cgroup subsys cpu
[    0.000000] Linux version 2.6.32-21-server (buildd@yellow) (gcc version 4.
4.3 (Ubuntu 4.4.3-4ubuntu5) ) #32-Ubuntu SMP Fri Oct 07 09:17:34 UTC 2011 (Ub
untu 2.6.32-21.32-server 2.6.32.11+drm33.2)
.............

You can make password less ssh access to the instance as follows:

ssh -i mykey.priv user@192.168.4.3

VM type has implications for harddisk size, amount of RAM and number of CPUs allocated to the instance. Check the VM types available.

sudo nova-manage instance_type list

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