Bug 694280 - RFE: libvirtd.conf: create max_ro_clients to protect max_clients
Summary: RFE: libvirtd.conf: create max_ro_clients to protect max_clients
Keywords:
Status: CLOSED DUPLICATE of bug 746666
Alias: None
Product: Red Hat Enterprise Linux 6
Classification: Red Hat
Component: libvirt
Version: 6.2
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: rc
: ---
Assignee: Eric Blake
QA Contact: Virtualization Bugs
URL:
Whiteboard:
Depends On:
Blocks: 747667 756082
TreeView+ depends on / blocked
 
Reported: 2011-04-06 20:47 UTC by Eric Blake
Modified: 2011-12-23 18:34 UTC (History)
5 users (show)

Fixed In Version:
Doc Type: Enhancement
Doc Text:
Clone Of:
Environment:
Last Closed: 2011-11-23 20:13:36 UTC
Target Upstream Version:


Attachments (Terms of Use)

Description Eric Blake 2011-04-06 20:47:11 UTC
Description of problem:
Right now, libvirt shares its client pool among read-only and read-write clients.  That means that enough parallel attempts to connect from read-only clients will starve any connection attempts by read-write clients.  This is a form of Denial of Service, built into the design, and it seems like it would be relatively easy to adjust things so that libvirt either has two separate client pools, or allows a smaller cap on the number of read-only clients, so that read-write clients can't be starved by too many read-only connections.

Version-Release number of selected component (if applicable):
libvirt-0.8.7-16.el6

How reproducible:


Steps to Reproduce:
1. if desired, modify /etc/libvirt/libvirtd.conf to reduce max_clients to make testing faster
2. open the maximum number (default 20) of simultaneous read-only connections (for example, a loop that spawns virsh -r into background processes)
3. try to open a read-write connection
  
Actual results:
starvation

Expected results:
Be able to guarantee a certain number of connections to read-write clients, no matter what read-only clients are doing

Additional info:

Comment 5 Dave Allan 2011-11-23 20:13:36 UTC
Closing as a duplicate of 746666 as the fundamental behavior that needs to be fixed is the same.

*** This bug has been marked as a duplicate of bug 746666 ***


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