Sep 15-19, 2008 EDOC 2008

Scheduling-capable Autonomic Manager for Policy-based IT Change Management System

H. AbdelSalam K. MalyR. Mukkamala M. Zubair

Department of Computer Science,Old Dominion University

D. KaminskyIBM, Raleigh, North Carolina

Sep 15-19, 2008 EDOC 2008

IT Change Management

• Managing large IT environments is expensive and labor intensive

• Using ad-hoc and human-based methodologies to manage Change Management in large size IT organizations can be costly, error prone and crisis oriented rather than targeted and predictable.

• One problem faced by IT administrators, in automating change management, is to arrive at a schedule for applying one or more change requests to the IT infrastructure

• In this paper, We provide two approaches to schedule change requests in the presence of organizational policies governing the use, access and availability of the IT infrastructure.

Sep 15-19, 2008 EDOC 2008

Scheduling Approaches

1. Calendar Based Approach

2. Time – Independent Policies

Sep 15-19, 2008 EDOC 2008

Calendar Based Approach

• Divide the week into time slots of equal size (h).

• At the beginning of each week as well as whenever the deployed policies or the infrastructure change, create a resource-slot matrix to store the relation between policies, resources, and time slots.

• For each resource (row) and in each time slot (column), the matrix entry specifies whether taking the specified resource down individually at the specified time slot would violate (value =1) any of the deployed polices or not (value=0).

Sep 15-19, 2008 EDOC 2008

To schedule a change request. There are two cases.

Case (i): If the request for change involves only one resource Scheduling information is already available in the matrix (i.e., time slots with a zero for the given resource row).

Case (ii): To schedule changes that involve more than one resource•Evaluate the logical OR between the rows of the resources in the request.•Due to redundancy, we need to reevaluate the policies at all the time slots with a zero for the given resource row. (See Next Figure)•Return only non violating time slots.

Calendar Based Approach (Cont.)

Sep 15-19, 2008 EDOC 2008

An example of resources dependency

• Router R2 Alone doesn’t violates Policy 1.• Taking Router R3 alone doesn’t violates Policy 1.• Taking R2 & R3 Down violates Policy 1.

Sep 15-19, 2008 EDOC 2008

Calendar Based Approach (Cont.)

ResourceSunday

12:00 AM- 1:00 AMMonday

8:00 AM- 9:00 AM…

Router R1 0 … 1 …

Router R2 0 … 0 …Router R3 0 … 0 …DB1 0 … 0 …DB2 0 … 0 …Application X 0 … 1 …

Example 1: Entries in a Time Slot-Resource Matrix

Sep 15-19, 2008 EDOC 2008

The idea behind is to represent each policy as a set of time-independent conditions and a set of time ranges when the policy is active.

Example:

“Application X must be available to students on weekdays from 7:00AM until 6:00PM”.

This policy can be expressed as

<“Application X must be available to students”, {Mon 7:00AM to 6:00PM, Tue on 7:00AM to 6:00PM …

Fri 7:00AM to 6:00PM} >.

Time-Independent Approach

Sep 15-19, 2008 EDOC 2008

Basic Algorithm

ScheduleAChange (change request Cnew)

Begin• T = Φ• For i = 1 to n

IF (Pi .violates. Cnew) Then T = T U Ti • For i = 1 to m

T = T U Qi • Return T’ (time range for the next week - T)

End

Sep 15-19, 2008 EDOC 2008

Improved Algorithm ScheduleAChangeImproved (change request Cnew)

Begin• T = Φ• For i = 1 to n

IF (Pi .violates. Cnew) Then T = T U Ti • For j = 1 to m {

C = Cnew U Ci

For i = 1 to n

IF (Pi .violates. C) Then T = T U Qi

}• Return T’ (time range for the next week - T)

End

Sep 15-19, 2008 EDOC 2008

Implementation

http://www.cs.odu.edu/~asalam/demo/scenario3/demo.html

Sep 15-19, 2008 EDOC 2008

Conclusion

• We proposed a simple calendar-based scheduler as well as one where policies are expressed as a pair of <time-independent policy, time of applicability> pair.

• This method of representing policies is novel and is shown to improve the efficiency of the scheduler.

• For small IT environments or for small schedule periods with a relatively large granularity, the calendar approach is found to be adequate.

• However, for larger environments, longer schedule periods, and a large number of policies, the time-independent approach is found to be essential due to its scalability