nova/doc/source/reference/vm-states.rst
Artom Lifshitz 50b9d28e7d Doc: rebuild can result in SHUTOFF VM state
Rebuilding a SHUTOFF instance keeps it in SHUTOFF [1]. The doc
incorrectly states that rebuilding always results in an ACTIVE state.
This patch corrects this.

[1] https://github.com/openstack/nova/blob/stable/rocky/nova/compute/manager.py#L3271-L3278

Change-Id: I1af725ec0d6db861e5aaac6f3338c2276e2dad5f
2019-01-10 12:03:17 -05:00

142 lines
5.1 KiB
ReStructuredText

Virtual Machine States and Transitions
=======================================
The following diagrams and tables show the required virtual machine (VM)
states and task states for various commands issued by the user.
Allowed State Transitions
--------------------------
.. graphviz::
digraph states {
graph [pad=".35", ranksep="0.65", nodesep="0.55", concentrate=true];
node [fontsize=10 fontname="Monospace"];
edge [arrowhead="normal", arrowsize="0.8"];
label="All states are allowed to transition to DELETED and ERROR.";
forcelabels=true;
labelloc=bottom;
labeljust=left;
/* states */
building [label="BUILDING"]
active [label="ACTIVE"]
paused [label="PAUSED"]
suspended [label="SUSPENDED"]
stopped [label="STOPPED"]
rescued [label="RESCUED"]
resized [label="RESIZED"]
soft_deleted [label="SOFT_DELETED"]
shelved [label="SHELVED"]
shelved_offloaded [label="SHELVED_OFFLOADED"]
deleted [label="DELETED", color="red"]
error [label="ERROR", color="red"]
/* transitions [action] */
building -> active
active -> active [headport=nw, tailport=ne] // manual layout
active -> soft_deleted [tailport=e] // prevent arrowhead overlap
active -> suspended
active -> paused [tailport=w] // prevent arrowhead overlap
active -> stopped
active -> shelved
active -> shelved_offloaded
active -> rescued
active -> resized
soft_deleted -> active [headport=e] // prevent arrowhead overlap
suspended -> active
suspended -> shelved
suspended -> shelved_offloaded
paused -> active
paused -> shelved
paused -> shelved_offloaded
stopped -> active
stopped -> stopped [headport=nw, tailport=ne] // manual layout
stopped -> resized
stopped -> rescued
stopped -> shelved
stopped -> shelved_offloaded
resized -> active
rescued -> active
shelved -> shelved_offloaded
shelved -> active
shelved_offloaded -> active
}
Requirements for Commands
-------------------------
================== ================== ==================== ================
Command Req'd VM States Req'd Task States Target State
================== ================== ==================== ================
pause Active, Shutoff, Resize Verify, unset Paused
Rescued
unpause Paused N/A Active
suspend Active, Shutoff N/A Suspended
resume Suspended N/A Active
rescue Active, Shutoff Resize Verify, unset Rescued
unrescue Rescued N/A Active
set admin password Active N/A Active
rebuild Active, Shutoff Resize Verify, unset Active, Shutoff
force delete Soft Deleted N/A Deleted
restore Soft Deleted N/A Active
soft delete Active, Shutoff, N/A Soft Deleted
Error
delete Active, Shutoff, N/A Deleted
Building, Rescued,
Error
backup Active, Shutoff N/A Active, Shutoff
snapshot Active, Shutoff N/A Active, Shutoff
start Shutoff, Stopped N/A Active
stop Active, Shutoff, Resize Verify, unset Stopped
Rescued
reboot Active, Shutoff, Resize Verify, unset Active
Rescued
resize Active, Shutoff Resize Verify, unset Resized
revert resize Active, Shutoff Resize Verify, unset Active
confirm resize Active, Shutoff Resize Verify, unset Active
================== ================== ==================== ================
VM states and Possible Commands
-------------------------------
============ =================================================================
VM State Commands
============ =================================================================
Paused unpause
Suspended resume
Active set admin password, suspend, pause, rescue, rebuild, soft delete,
delete, backup, snapshot, stop, reboot, resize, revert resize,
confirm resize
Shutoff suspend, pause, rescue, rebuild, soft delete, delete, backup,
start, snapshot, stop, reboot, resize, revert resize,
confirm resize
Rescued unrescue, pause
Stopped rescue, delete, start
Soft Deleted force delete, restore
Error soft delete, delete
Building delete
Rescued delete, stop, reboot
============ =================================================================
Create Instance States
----------------------
The following diagram shows the sequence of VM states, task states, and
power states when a new VM instance is created.
.. image:: /_static/images/create-vm-states.svg
:alt: Sequence of VM states, task states, and power states when a new
VM instance is created.