visualization of monitoring data at the nasa advanced ... · † staff hud and nagios web interface...

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Toward a socioecological model of gentrification: How people, place, and policy shape neighborhood change Alessandro Rigolon a and Jeremy Németh b a University of Illinois at UrbanaChampaign; b University of Colorado Denver ABSTRACT Researchers have determined many of the factors that make neighbor- hoods susceptible to gentrification, but we know less about why some gentrification-susceptible neighborhoods gentrify and others do not. Some studies claim that internal neighborhood features such as historic housing stock are the most powerful determinants of gentrification, whereas other studies argue that a lack of strong affordable housing policies is the primary driver of neighborhood change. In this article, we move beyond a focus on singular determinants to recognize the interplay between these variables. We develop a socioecological model of gentrifica- tion in which we characterize neighborhood change as shaped by nested layers we categorize as people (e.g., demographics), place (e.g., built envir- onment), and policy (e.g., housing programs). We then test the model in the five largest urban regions in the United States to begin to determine which variables within the people, place, and policy layers best predict whether a neighborhood will gentrify. Introduction In neighborhoods in strong housing markets such as Amsterdam, Melbourne, San Francisco, and Toronto, gentrification has become the new normal(Carpenter & Lees, 1995; Caulfield, 1994; Maciag, 2015; Shaw, 1999; Van Gent, 2013). Under advanced capitalism, gentrification sometimes seems inevitable: Deutsche (1996) claims that gentrification is the residential component of urban redevelopment(p. xiv), and Brahinksy (2014) suggests that it is essentially our economys urban form(p. 52). Insofar as gentrification can result in the forced displacement of existing residents, planners, policymakers, scholars, and activists are continually seeking new forms of resistance to the most damaging consequences of this phenomenon. But what should be the target of such resistance initiatives? By identifying the relative explanatory power of different determinants of gentrification, political leaders can no longer blame the market,a tactic that obscures the fact that local institutions, place quality, and housing programs in fact create the contours and parameters of housing markets. And armed with such knowledge, planners, policymakers, and community leaders can more accurately target their antigentrification initiatives and move the dial toward solutions that more effectively improve the quality of life of their most vulnerable residents. In this article, we develop an operational socioecological model of gentrification that views this phenomenon as a result of a number of individual behaviorsthat is, residential relocation choicesthat occur in response to the complex interplay between person- and environment-focused factors. We then test our new model in a three-step empirical research process across five U.S. regions. This test CONTACT Alessandro Rigolon [email protected] Department of Recreation, Sport and Tourism, University of Illinois at UrbanaChampaign, 219 George Huff Hall, 1206 S 4th St, Champaign, IL 61820. Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/ujua. © 2019 Urban Affairs Association JOURNAL OF URBAN AFFAIRS https://doi.org/10.1080/07352166.2018.1562846

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Page 1: Visualization of Monitoring Data at the NASA Advanced ... · † Staff HUD and nagios web interface † clicking on Staff HUD goes to the nagios web page – for the service checks

Visualization of Monitoring Data at the NASA Advanced Supercomputing FacilityJanice [email protected]

https://ntrs.nasa.gov/search.jsp?R=20140010807 2020-03-23T14:06:47+00:00Z

Page 2: Visualization of Monitoring Data at the NASA Advanced ... · † Staff HUD and nagios web interface † clicking on Staff HUD goes to the nagios web page – for the service checks

NASA Advanced Supercomputing Facility

• Pleiades– 11,136-node SGI ICE supercluster

162,496 cores total (32,768 additional GPU cores)• Tape Storage

– pDMF cluster• NFS servers

– home filesystems on computing systems• Lustre Filesystems

– each filesystem is multiple servers• PBS (Portable Batch System)

– job scheduler that runs on computing systems

Ref: http://www.nas.nasa.gov/hecc/Janice Singh - [email protected] 2

Page 3: Visualization of Monitoring Data at the NASA Advanced ... · † Staff HUD and nagios web interface † clicking on Staff HUD goes to the nagios web page – for the service checks

Why Visualization is Needed

• 24 x 7 Help Desk– need a quick overview of system status

• but still more specific than nagios visualization– not just single status per host, but sub-groups per host

– they assess situations before calling next level of support• automatic alerts from nagios are not as selective

– interrelated issues• allows us to see how many systems affected by one issue

Janice Singh - [email protected] 3

Page 4: Visualization of Monitoring Data at the NASA Advanced ... · † Staff HUD and nagios web interface † clicking on Staff HUD goes to the nagios web page – for the service checks

Heads Up Display – For Staff

Janice Singh - [email protected] 4

Page 5: Visualization of Monitoring Data at the NASA Advanced ... · † Staff HUD and nagios web interface † clicking on Staff HUD goes to the nagios web page – for the service checks

Heads Up Display – For Staff (details)

Janice Singh - [email protected] 5

Page 6: Visualization of Monitoring Data at the NASA Advanced ... · † Staff HUD and nagios web interface † clicking on Staff HUD goes to the nagios web page – for the service checks

Heads Up Display – for Users

Janice Singh - [email protected] 6

Page 7: Visualization of Monitoring Data at the NASA Advanced ... · † Staff HUD and nagios web interface † clicking on Staff HUD goes to the nagios web page – for the service checks

All the Parts

• nagios

• nrpe

• nsca

• datagg (in-house software)

• apache

• perl/cgi-bin

Janice Singh - [email protected] 7

Page 8: Visualization of Monitoring Data at the NASA Advanced ... · † Staff HUD and nagios web interface † clicking on Staff HUD goes to the nagios web page – for the service checks

Data flow

network firewall (The Enclave)nsca

nsca

nrpe

ssh

Cluster

Compute Node

Remote Node

Web Server

nagios

nsca nagios.cmd

datagg

nagios2.cmd

nagios

nagios

nagios web interface

HUD orange - pipe filegreen - flat filepurple - web site

HUD buffer

nrpe nrpe

Dedicated Nagios Node

Janice Singh - [email protected] 8

Page 9: Visualization of Monitoring Data at the NASA Advanced ... · † Staff HUD and nagios web interface † clicking on Staff HUD goes to the nagios web page – for the service checks

Nagios (and add-ons) setup

The Basics•the webserver and the main nagios server are the same machine•there is a network firewall called “the enclave”

– most compute nodes are inside the enclave– the webserver can only receive data from the enclave, not

send•the servers within the enclave send nagios data to the webserver via nsca•for the servers outside the enclave, nrpe is used•plugins written in Perl using Nagios::Plugin

Janice Singh - [email protected] 9

Page 10: Visualization of Monitoring Data at the NASA Advanced ... · † Staff HUD and nagios web interface † clicking on Staff HUD goes to the nagios web page – for the service checks

Nagios (and add-ons) setup, cont.

Versions• when I inherited the systems, they were all using nagios 2.10

– most systems have been upgraded to nagios 3.4+– all new systems have nagios 3.5– webserver is still using 2.10

• nsca 2.7.2 across the board

Janice Singh - [email protected] 10

Page 11: Visualization of Monitoring Data at the NASA Advanced ... · † Staff HUD and nagios web interface † clicking on Staff HUD goes to the nagios web page – for the service checks

Nagios (and add-ons) setup, cont.

Clusters within the enclave• there is one host that is considered the Dedicated Nagios Server• the rest of the hosts are monitored using nrpe • exceptions on Pleiades:

– there are many hosts monitored that get reimaged often• difficult to administer nrpe• use check_by_ssh

– ssh is flaky under nagios 3, so it still uses nagios 2.10• will randomly give the error: Could not open pipe: /usr/bin/ssh

– use 2 Dedicated Nagios Servers• so many checks that there was unacceptable latency

– tests that should run every 2 mins were running every 30 mins

Janice Singh - [email protected] 11

Page 12: Visualization of Monitoring Data at the NASA Advanced ... · † Staff HUD and nagios web interface † clicking on Staff HUD goes to the nagios web page – for the service checks

datagg (DATa AGGregator)

• why it was needed (i.e. what nagios couldn’t do for us)– error summaries of nagios problems

• the nagios webpage does tell number of alerts per service group, but that cannot be leveraged via API

Janice Singh - [email protected] 12

Page 13: Visualization of Monitoring Data at the NASA Advanced ... · † Staff HUD and nagios web interface † clicking on Staff HUD goes to the nagios web page – for the service checks

datagg (DATa AGGregator), cont.

• why it was needed (i.e. what nagios couldn’t do for us)– parsing data about Portable Batch System (PBS)

– piecing together large outputs from NSCA• current output from PBS: 404,937 characters

Janice Singh - [email protected] 13

Page 14: Visualization of Monitoring Data at the NASA Advanced ... · † Staff HUD and nagios web interface † clicking on Staff HUD goes to the nagios web page – for the service checks

datagg (DATa AGGregator), cont.

• why it was needed (i.e. what nagios couldn’t do for us)– mapping service nodes to the appropriate Lustre filesystem

• they are in a servicegroup (but not available via API)

Janice Singh - [email protected] 14

Page 15: Visualization of Monitoring Data at the NASA Advanced ... · † Staff HUD and nagios web interface † clicking on Staff HUD goes to the nagios web page – for the service checks

datagg (DATa AGGregator), cont.

• in-house written perl script– it reads the command file (pipe) that nsca creates on the

webserver– the nagios configuration on the webserver also writes to the

nsca command file– it aggregates the data that it reads in from the pipe and writes

it out to a flat file referred to as the “HUD buffer”• The data read in is in the format:

[$timestamp] PROCESS_SERVICE_CHECK_RESULT; $hostname; $service_description; $state; $output

Janice Singh - [email protected] 15

Page 16: Visualization of Monitoring Data at the NASA Advanced ... · † Staff HUD and nagios web interface † clicking on Staff HUD goes to the nagios web page – for the service checks

HUD Buffer

• is a Windows-style .ini file– sections

• used to group together the boxes (or sub-boxes)• ex: [pleiades daemons]

– keys• name=value

– this is where we put the nagios state and output of plugin

– every section also has the key Error Summary

Janice Singh - [email protected] 16

Page 17: Visualization of Monitoring Data at the NASA Advanced ... · † Staff HUD and nagios web interface † clicking on Staff HUD goes to the nagios web page – for the service checks

Data flow

network firewall (The Enclave)nsca

nsca

nrpe

ssh

Cluster

Compute Node

Remote Node

Web Server

nagios

nsca nagios.cmd

datagg

nagios2.cmd

nagios

nagios

nagios web interface

HUD orange - pipe filegreen - flat filepurple - web site

HUD buffer

nrpe nrpe

Dedicated Nagios Node

Janice Singh - [email protected] 17

Page 18: Visualization of Monitoring Data at the NASA Advanced ... · † Staff HUD and nagios web interface † clicking on Staff HUD goes to the nagios web page – for the service checks

Displays

• Two versions– Internal (aka Staff HUD) on the internal network

• Staff HUD and nagios web interface• clicking on Staff HUD goes to the nagios web page

– for the service checks for the host or service group– the nagios web interface gives more details on the

plugin output than is displayed on the HUD– the nagios web interface is used to suspend/restart

notifications– External (aka miniHUD)– Permissions set in the Apache config file

• Both written in Perl using cgi-bin

Janice Singh - [email protected] 18

Page 19: Visualization of Monitoring Data at the NASA Advanced ... · † Staff HUD and nagios web interface † clicking on Staff HUD goes to the nagios web page – for the service checks

Future Plans

• use a database to collect data– this will also allow us to have historical data beyond what is in

the logs, which can be used in graphing– will eliminate the need for a flat file

Janice Singh - [email protected] 19

Page 20: Visualization of Monitoring Data at the NASA Advanced ... · † Staff HUD and nagios web interface † clicking on Staff HUD goes to the nagios web page – for the service checks

Future Plans

• things that would be great to see in nagios 4– an API– make a nagios check run “on demand”– no more random “could not open pipe” errors– lower latency (we’re having problems with less than 600

checks!)– error summaries– way to send large amounts of data via nsca– a way to see the exact command that nagios ran on the

nagios webpage

Janice Singh - [email protected] 20

Page 21: Visualization of Monitoring Data at the NASA Advanced ... · † Staff HUD and nagios web interface † clicking on Staff HUD goes to the nagios web page – for the service checks

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Janice Singh - [email protected] 21