The Architecture Practice team in Professional Services have been writing articles to assist the community to plan, design and deploy ArcGIS Enterprise. This purpose of this page is to be a single resource to all these blogs and will be updated as new posts are created.

This is the second article in the GIS Enterprise Reporter series.  The focus of this article is to offer a bit of guidance for running the application.

GIS Enterprise Reporter allows you to clearly document existing deployments of ArcGIS Enterprise (Portal for ArcGIS, federated ArcGIS Server Sites, ArcGIS Data Stores, etc.).  You can use this tool to document and compare deployments in different environments, understand changes over time, etc.

Please note that this tool is not a product of Esri.  It is a tool produced by an employee of Esri and made broadly available in the hopes that it will be useful.  It is provided "as is".

Network Analyst has always been in-demand capability of ArcGIS Enterprise as it provides popular problem solving analysis types such as Route, Service Area, Closest Facility and Origin-Destination Cost Matrix.

This Article contains a walk-through for load testing a route solver service (map-based service) with an Apache JMeter Test Plan. It uses a public accessible dataset in the examples for the data generation and test configuration process. However, the testing procedure should work when using any valid network dataset. This Article assumes you are familiar with Apache JMeter and some of the Test Plan strategies we have been using in other discussions.

Table Of Contents

• Network Analyst Route
• Load Testing a Network Analyst Route Service
• How to Test a Network Analyst Route Service?
  • Network Analyst ArcGIS Pro Tutorial Data
  • Test Data Generation
    • Making the Tools Available from ArcGIS Pro
    • Launch the Generate Data (Solve Route) Tool
    • The Generate Data (Solve Route) Tool Inputs
    • Spatially Visualize the Generated Points
• The Route Solver Test Plan
  • HTTP Request
  • The Thread Group Configuration
• Validating the Test Plan
  • Transactions
  • Requests
• Test Execution
• JMeter Report
  • Throughput Curve
  • Performance Curves
• Final Thoughts

If you have a multiple-machine Portal for ArcGIS or ArcGIS Server site, you have a dependency on a file share.  If you are having a problem with your site, how do know whether the file share might be causing it?  This article is intended to help with that challenge.

As the foundational software system for GIS, ArcGIS Enterprise performs many duties such mapping and visualization, analytics. If one function were to be used as a benchmark for testing an ArcGIS Enterprise deployment, a strong case can be made for the map service export function. Export map can be called easily in an Apache JMeter Test Plan by varying the spatial extents of the requests across several map scales.

This Article provides a discussion on the key components of running such a benchmark like the dataset, service instances and step load. For comparison purposes, results are also listed of the benchmark performed within an Esri test environment.

Table Of Contents

• Choosing a Capability of ArcGIS Enterprise to Benchmark
• What is a Benchmark of a Map Service?
• Benchmark Dataset
  • What is Public Domain Data?
  • Why Use Public Domain Data?
  • SampleWorldCities vs Natural Earth
    • The Benchmark Natural Earth Dataset
  • Deployment Architecture
  • Data Source Type and Location
  • Service Type and Number of Instances
  • Do the Request Options in a Benchmark Test Matter?
• The Map Service Benchmark Test Plan
  • The Thread Group Configuration
• Benchmark Test Execution
• Results and Analysis
  • The Ideal Throughput Curve
  • The Ideal Performance Curve
• JMeter Report
  • Actual Throughput Curve
  • Actual Performance Curve
• Comparing the Results

Security requirements and policies vary between organizations, and different deployment patterns are required to meet those requirements and constraints. In this post I will try to address some of the more common security requirements and suggest deployment patterns to satisfy those requirements.

In my previous article, Architecture is a Funny Word, I introduced Esri’s Global Architecture Team. I talked a bit about the work we do (and don’t do) and how we can support you in your efforts to design, build, and implement a GIS that makes a real difference at your organization. You might want to check that blog out first, since it sets up some of the context for this one. However, if you think context is dull and overrated, then by all means carry on, dear reader.

While everyone uses both sides of their brain, it is said that ‘right-brained’ people tend to be creative, imaginative and innovative thinkers. They like to employ creative concepts to understand complex ideas, are often focused more on the ‘big picture’ rather than specific details. ‘Left-brained’ people are said to be detail-oriented, analytical, and logical thinkers. They like to approach problems methodically and with concrete evidence and facts, and know that people don’t trip over mountains, but over molehills.

It seems to me that GIS practitioners are a diverse mix of right and left-brainers. Which makes sense, since GIS is as much about analyzing data and identifying patterns as it is about communicating concepts and ideas with beautiful, compelling visuals. So, I figured it could be valuable (and fun) to try and explain architecture in a way that would appeal to a larger group of thinkers.

The Right Brain
For my right-brained readers, I offer you an architecture analogy: Architecture is often compared to the architecture of the physical world of buildings, bridges, or even city planning. This analogy illustrates some key facets of the discipline- describing ‘what should be’ in terms of design, and how it should be adjusted going forward. However, this analogy only describes some of what architects do, and sometimes the ‘how’ and ‘why’ are more interesting, especially to you right-brainers, than the ‘what’. So why don’t we take a new analogy for a spin?

The fundamental idea of “yin-yang” is that seemingly opposite or contrary forces are actually complementary and interrelated. If you’ve ever sat in a room with technologists and business people trying to solve a problem together, you might see how those 'seemingly opposite forces' could represent business and technology. Technologists often feel separated from the business objectives of their organization, and business people sometimes see technology as a frustrating, separate field from their work. Of course, these two practices are completely interrelated and dependent on each other: the business dictates the use of technology, and technology guides and enables what’s possible for the business to achieve.

One of the key tenets of an architect’s duty is to make this relationship strong and clear by aligning the capabilities of technology to the needs of the business. In other words, we strive to highlight and strengthen the interconnectedness of these sometimes seemingly opposing forces. We do this by starting with a vision everyone can agree on and collectively work toward. Almost as importantly, we also need to make that alignment easier to see and understand, especially for leadership and other key stakeholders. This means communicating creatively, often with visuals, to explain complex ideas. Anyone who has had to act as the bridge between business and technology knows that bridge’s foundation relies more heavily on the art of building relationships than the science of technicalities.

The Left Brain

Alright, left-brained readers, it’s your time to shine. Let’s get serious about the methodical, concrete work architects on the Global Architecture team can do with you. Our work revolves around three key questions:

1. Where is your organization today?
2. Where do you need to be tomorrow?
3. What’s the best path to get there?
   
   

Notice how I didn’t say:

1. What does your GIS do today?
2. What do you want to do with GIS tomorrow?
3. Here’s what you need to buy or install to do it

Rather, we take a business-first approach to ensure that your investment in GIS is directly impacting outcomes for your organization and its stakeholders. We start by understanding the business challenges impeding your organization’s goals, and design new or augmented business workflows that resolve those challenges. Then, we identify what technology components, information, data, and skills are needed to enable those workflows. This process draws clear connections between technology solutions and business outcomes for your executive sponsors (or potential executive sponsors).

This work can’t be done in isolation. An architect documents perspectives from both the business and technology side before defining how to meet their needs in an efficient, sustainable and adaptable way. This means that architects speak the languages of both technologists and business managers. One way we do this is with diagrams. Kind of how GIS practitioners communicate with maps.

While technical architects communicate with system diagrams, my team and I communicate with conceptual and logical architecture diagrams. These might take the shape of a matrix illustrating where technology is not being effectively leveraged in your organization, a flow diagram outlining a new or augmented business workflow, or a roadmap that details how to get from where you are now to a place where you can overcome the challenges impeding your goals.

Let’s Connect

As Esri’s User Conference is just around the corner, I suspect many of you are getting excited to talk about the future for GIS at your organization. The Global Architecture Team is excited to work with you. Come chat with us. If you have any questions or would like to talk about any of these ideas further, email me at sscher@esri.com. You can also reach my team at global_archiecture@esri.com.

“Nothing is as dangerous in architecture as dealing with separated problems” – Alvar Aalto

Like many of my colleagues on the Global Architecture Team at Esri, I spend a lot of time explaining who we are and what we do, and I think I know why. architecture is a funny word. It means a lot of different things to a lot of different people, which makes sense because depending on your domain, your experience with architects will differ greatly.

You might think of data architects, who design how data is collected, stored and arranged. Perhaps you’re more familiar with application architects, who are concerned with how applications are used and how they work together. Many people think of system architecture, and quickly find themselves in a cold sweat after picturing a horrifyingly complex system diagram. All this preamble to say: The Global Architecture Team doesn’t really do any of that.

What We Do

Our work is more closely aligned to the discipline of enterprise architecture. The role of the enterprise architect is to align the perspectives of business, applications, data, and technology to the organization’s overall strategy, while making sure the design follows organizational governance policies and standards. Now, we obviously we work at Esri, so we aren’t going to architect your entire business-technology landscape (sorry). Rather, we use enterprise architecture principles and frameworks and apply them specifically to the domain of GIS. One of those principles you’ll hear us talk about a lot is to take a ‘top-down, business first approach’.

This means starting with a vision for how GIS needs to support your business. This isn’t a list of maps or apps, and it definitely isn’t a data catalog. Rather, it’s a statement of what your organization will ‘look’ like when it has implemented and is operationalizing GIS effectively. Then we need to understand what business processes need to be designed or augmented with GIS. More simply, we figure out how the work your staff does needs to change to achieve the vision. Only once we have this level of understanding do we start aligning technology components, information products and data needed to enable those new or enhanced processes. Ultimately, we work with you to design the ‘why’ and then the ‘who’, ‘what’, ‘where’, and ‘how’ of GIS in your organization. My colleagues on the Global Architecture team and I are here to work with you to design the most impactful GIS that’s feasible in terms of sustainability, cost, and potential risk.

Let’s Connect

As Esri’s (first-ever virtual) Users Conference(esriuc2020) rapidly approaches, we know many of our customers are eager to connect and learn how they can do more. The Global Architecture team has supported organizations large and small, and in nearly every industry in their efforts to transform the way their organization works with geography and GIS. If you found this blog interesting and are looking for more on how our team can help amplify your success, you can reach me at sscher@esri.com or my team at global_architecture@esri.com.

“An idealist believes the short run doesn’t count. A cynic believes the long run doesn’t matter. A realist believes that what is done or left undone in the short run determines the long run.” - Sydney Harris

• Introduction
• ArcGIS Web Adaptor
• Web Context URL
• External Access and DNS
• URLs used in federation
• Services URL
• Administrative URL
• Private portal URL
• Load Balancer Configuration
• Health Check Settings
• Throttling
• Sticky Sessions
• Layer 4 vs. Layer 7
• Summary of Recommendations
• Certificates

Introduction

Organizations often require a certain level of system uptime for their ArcGIS Enterprise deployments, such as 99 percent of the time or higher. For these organizations, implementing a strategy to ensure high availability is crucial.

High Availability (HA), while related to Disaster Recovery (DR), is a separate concept. Generally, HA is focused on avoiding downtime for service delivery, whereas DR is focused on retaining the data and resources needed to restore a system to a previous acceptable state after a disaster.

This post will focus on best practices to configuring local load balancer (Local Traffic Manager, LTM) in a single location for high availability, and will not include considerations to configuring Global Traffic Manager (GTM) for automatic failover between different locations.

To achieve high availability, you must reduce single points of failure through duplication and load balancing.

Load balancers act as a reverse proxy and distribute traffic to back-end servers. Third-party load balancer is required in a highly available ArcGIS Enterprise deployment to improve the capacity and reliability of the software. They handle client traffic to your portal and server sites, as well as internal traffic between the software components.

ArcGIS Web Adaptor

Though ArcGIS Web Adaptor is considered a load balancer, it’s inadequate to serve as the lone load balancer in a highly available deployment, since ArcGIS Web Adaptor also requires redundancy to achieve high availability.

ArcGIS Web Adaptor is an optional component, as load balancers can forward requests directly to your portal and server sites, yet it is a recommended component. The advantages of using web adaptors are:

• It provides an easy way to configure a single URL for the system
• It allows you to choose context names for the different system components, e.g. portal, server, mapping, etc.
• It is integrated natively with other ArcGIS Enterprise software components, the portal and server sites, and will automatically handle health checks and configuration tasks, e.g. adding new machine to a server site

Web Context URL

The web context URL is the public URL for the portal. Since any item in portal has a URL - file, layer, map, and app, the portal's WebContextURL property helps it construct the correct URLs on all resources it sends to the end user.

External Access and DNS

ArcGIS Enterprise portal supports only one DNS for public portal URL (the web context URL), and currently there is no supported way to change the web context URL without redoing administrative tasks, e.g. federating server sites with your portal. If your ArcGIS Enterprise requires external access, e.g. to allow access to mobile users, contractors, partners, or agencies, without VPN, or if you anticipate that you will need to allow external access in the future, you must use an externally resolvable DNS name for the portal’s web context URL, e.g. https://gis.company.com/portal.

To secure external access to ArcGIS Enterprise, it is common to host a load balancer in a DMZ, and implement a Split Domain Name System (Split DNS), i.e. internal access to ArcGIS Enterprise DNS (e.g. gis.company.com) will be resolved to an internal load balancer IP, so internal users will stay behind the firewall, and external access to ArcGIS Enterprise DNS will be resolved to an external (DMZ) load balancer IP.

URLs used in federation

Several different URLs are used in a highly available ArcGIS Enterprise deployment.

Services URL

This is the URL used by users and client applications to access ArcGIS Server sites. It’s the URL for the load balancer that handles ArcGIS Server traffic and passes requests either to the server site’s Web Adaptor or directly to the server machines.

Administrative URL

This URL is used by administrators, and internally by the portal, to access an ArcGIS Server site when performing administrative operations. This URL is also used for publishing GIS services with reference to a registered data store, e.g. SQL Server enterprise geodatabase, to a federated server site. This must direct to a load balancer; if the administrative URL points to a single machine in the server site and that machine is offline, federation will not work. This can be the same URL as the services URL or can be a second load balancer (VIP) for each federated server site admin URL via port 6443. Configuring a dedicated VIP for each federated server site admin URL via port 6443 will require to open this port for administrators and publishers, and you can disable administrative access through the web adaptor, thus providing additional security controls for the organization.

I recommend using the same URL as the services URL since it simplifies configuration. ArcGIS Server administrative access will be controlled by ArcGIS Enterprise authentication and user roles, similarly to administrative access to portal, e.g. ArcGIS Portal Directory (portaladmin) and Organization Settings. To use web adaptor URL for administrative URL, you must enable administrative access in the server web adaptor.

Private portal URL

This is an internal URL used by your server sites to communicate with the portal. This must also direct to a load balancer and should be defined prior to federating. If you federate your server sites prior to setting the privatePortalURL, follow step 8 and 9 in the topic Configure an existing deployment for high availability to update the URL within your deployment. Similar to the administrative URL, this can be the same as the public URL for the portal (portal’s web context URL), or it can be a second load balancer (VIP) via port 7443.

For configuration simplicity, I would recommend using the public URL for the portal for the private portal URL. If you choose to use a dedicated load balancer VIP via port 7443 for private portal URL, you should configure the load balancer to check the health of the portal machines.

Load Balancer Configuration

Health Check Settings 

The most important capability to use is a Health Check. As described in portal’s health check documentation:

“The health check reports if the responding Portal for ArcGIS machine is able to receive and process requests. For example, before creating the portal, the health check URL reports the site is unavailable because it can't take requests at that time.”

ArcGIS Enterprise portal and server have health checks.

When you use ArcGIS Web Adaptors, the web adaptors will take care of performing the health checks against the portal and the servers. In this case you can configure the load balancer with basic TCP/443 health check or a static page health check, with standard health check settings for timeout, failure trigger, polling interval, and healthy threshold.

If you configure the load balancer to access portal and/or the servers directly, e.g. if you don’t include web adaptors in your architecture, or if you use dedicated load balancer URL for private portal URL (port 7443) or federated server administrative URL (port 6443), you should configure the load balancer to check the health of the portal and server machines.

There are some important considerations about health check settings on the load balancer. Most organizations using a load balancer use a static page as their health check (e.g. index.html) to determine whether the web server is healthy. This is a static file that only requires a disk fetch.  Also, most web servers tend to bottleneck with I/O rather than CPU. 

However, Esri’s ArcGIS Server is different in that our health check requires a very small amount of CPU because our check is more than just a disk fetch, as the software needs to determine whether certain processes are functional.

With health checks there is a timeout value on the poll. Most load balancer administrators set the timeout value very low because disk fetches are usually very fast (though they often leave some buffer for poor network latency).

When using a low timeout value with ArcGIS Server and when using a multi-machine setup, there is a chance one of the machines may exceed the low timeout value and a healthy machine will be removed.

Esri recommends a higher timeout value, ideally at least 5 seconds. Depends on the system, you might need to increase this value even more. You should monitor your environment and adjust this value accordingly. This may seem like a high number to Network Administrators since a health check on a simple page usually takes less than 10ms normally (plus network latency).

However, it is critical for the load balancers to distinguish between when a machine is just slow vs. when a machine is truly dead and non-responsive.  If portal or server is truly down and not listening on a port at all, most load balancers will detect this even sooner than 5 seconds, so this timeout does not impact "normal" failures where a machine goes away.

The second consideration is the failure trigger - how many times does the poll need to fail before removing the machine from the load balancer. 

As a rule, Network Administrators set the failure trigger to be more than 1 failure because they do not want a single network glitch to take down the system.  As noted above, a small spike in CPU usage (which is common on ArcGIS Server systems) can cause a timeout, and it is not desirable to bring down a machine because of a single CPU spike on a single machine. 

Esri has done significant internal testing with load balancers and found that a setting of 5 failures dramatically reduced the number of false positives while still detecting true outages.  We found that a value of 3 was still highly susceptible to false positives.

The third consideration is the polling interval.  Esri has found that 30 second polling intervals, coupled with 5 failures was a sweet spot of detecting true failures and ignoring false positives. 

With this combination, the expected value (using a statistics term) or mean time to detection is 1 minute and 15 seconds of downtime before detection, with a worse case of 2 minutes and 30 seconds.  It is possible to aim for a lower mean time to detection, but the trade-off is receiving false positives.

If the lower mean time to detection is preferred, it may be needed to increase capacity so there are sufficient resources to suffer a true failure on a machine and a false positive without overloading the remaining machines.

The final setting regarding health checks is the healthy threshold for the load balancer to start sending requests again.  Esri does not have a recommendation for this and we have not observed many differences in this number, but we typically see 3 healthy consecutive polls before rejoining.

Throttling 

Throttling settings are worth considering.  ArcGIS Server is CPU-bound which means most of the request time is spent using the CPU rather than waiting for I/O. 

This means if there are 8 cores, ArcGIS Server can handle a little more than 8 simultaneous requests from a practical standpoint. If ArcGIS Server is busy, it starts queueing requests until there are hundreds of requests in line, and after that threshold it refuses connections. When there is a long backlog of requests it will result in a long wait time, but eventually the request gets processed.

ArcGIS Server has settings to control this behavior, so there are less of these abandoned requests being worked on, but it is also a best practice to control this at the load balancer level via its ability to throttle. 

Esri does not have a numerical recommendation because it depends a lot on the specific architecture and the types of requests coming in, but it is typical to throttle at a significant lower value than Network Admins would typically do for a Web Server.

This is beyond the control of the Network Administrator, but the client applications should be written to handle a throttling event and do re-tries in increasing time intervals (e.g. first time you can immediately re-try, second time you wait a second, third re-try wait 5 seconds, etc.).

Sticky Sessions 

Esri does not recommend sticky sessions except in very rare circumstances. Sticky sessions can theoretically overload a machine.  Esri has conducted load tests using sticky sessions to see if we found results that would overload our GIS Server, and this did not occur. We have also not received any customer complaints. That said, since our software is stateless we do not see the value in using sticky sessions. 

Layer 4 vs. Layer 7 

The final setting to mention is whether the load balancer does a "level 7" approach or a "layer 4" approach.  This can be a debate among Network Administrators, but below is a concise summary of the situation describing the differences and advantages of each.

A layer 7 load balancer understands http and https, it therefore decrypts https content and then re-encrypts it.  Because it understands http and https it can cache content and save requests going to the backend server. 

A layer 4 load balancer views all the traffic as TCP packets and has no idea what the packets mean; they could be for ftp, https, smtp, but this does not matter to a layer 4 load balancer.  As a result, it doesn't need to understand the http payload and can be faster.

ArcGIS Server can work with either approach and there is no recommendation on this setting for Network Admins, but there are some pieces of information that an Admin will want to be aware of. 

ArcGIS Server payloads can be much larger than HTML pages, CSS, and JS content (the actual amount would be useful but is often dependent on the data the customer uses).  This means there is more CPU load on a layer 7 load balancer decrypting and encrypting on a per-request basis. 

Also, since much of ArcGIS Server data is dynamic and frequently changing, by default cache headers prohibit caching on the client and load balancer. If the data doesn't change much and the customer wants to use a layer 7 load balancer, they can change and control these cache settings. 

Summary of Recommendations

Health Check

• If you configure your load balancers with ArcGIS Web Adaptors, you can configure the load balancer with basic TCP/443 health check or a static page health check against the web servers
• If you configure the load balancer to access portal and/or the servers directly (via ports 6443 and 7443), use HTTPS health check endpoint:
  • Portal:
    • Request: https://<host>/<webadaptor>/portaladmin/healthCheck?f=json
      OR
      https://<host>:7443/arcgis/portaladmin/healthCheck?f=json
    • Response: {"status":"success"}
  • Server:
    • Request: https://<host>/<webadaptor>/rest/info/healthCheck?f=json
      OR
      https://<host>:6443/arcgis/rest/info/healthCheck?f=json
    • Response: {"success":true}
  • Use a higher health check timeout value, at least 5 seconds
  • Use a value of 5 for the failure trigger
  • Use 30 second polling intervals
  • Use 3 healthy consecutive polls before rejoining

Throttling

• Use a throttle setting at a significant lower value than typical web servers

Sticky Sessions

• Do not use sticky sessions

Certificates

ArcGIS Enterprise components come pre-configured with a self-signed server certificates, which allows the software to be initially tested and to help you quickly verify that your installation was successful. However, in almost all cases, an organization should request a certificate from a trusted certificate authority (CA) and configure the software to use it. The certificate can be signed by a corporate (internal) or commercial CA. Commercial CA (known-CA) must be used for externally resolvable DNS, e.g. load balancer VIP DNS; internal domain certificates can be used for internal servers. 
For ArcGIS Enterprise system with externally resolvable DNS, if the load balancer’s SSL method is SSL-passthrough (the load balancer does not decrypt and re-encrypt https content), it does not require certificate, and a commercial CA certificate must be installed on the mapped servers (e.g. web servers where the web adaptors are installed). If the load balancer’s SSL method is SSL re-encryption, a commercial CA certificate must be installed on the load balancer.