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VMware Hands-on Labs

Use our Browser / Network Compatibility Test tool before you start your lab experience ..

Friends,

Some great news !

The VMware Learning Platform engineering team put together a very cool Tool to help you do a little sanity check before you take a Hands-on Lab. It will check your browser compatibility, and some basic network sanity checks to make sure your lab experience is as best as can be.

Be sure to send us your feedback and if you think its useful tell a friend.

Link:http://www.vmwlp.com/HOL/compatibility/

The post Use our Browser / Network Compatibility Test tool before you start your lab experience .. appeared first on VMware Hands-On Lab (HOL) Blog.

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Use our Browser / Network Compatibility Test tool before you start your lab experience ..

Friends,

Some great news !

The VMware Learning Platform engineering team put together a very cool Tool to help you do a little sanity check before you take a Hands-on Lab. It will check your browser compatibility, and some basic network sanity checks to make sure your lab experience is as best as can be.

Be sure to send us your feedback and if you think its useful tell a friend.

Link:http://www.vmwlp.com/HOL/compatibility/

The post Use our Browser / Network Compatibility Test tool before you start your lab experience .. appeared first on VMware Hands-On Lab (HOL) Blog.

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Join us for Americas vForum Online June 28th – Tons of great Sessions and Hands-on Labs

Folks,

We will be hosting another vForum Online event this June 28th and have great Sessions andHands-on Labs lined up to make your learning experience even better. These events are exciting as we engage with users from all of the Americas. We will be online monitoring the infrastructure and answering questionsfrom you.

We look forward to seeing you there !

See Agenda

REGISTER NOW

The post Join us for Americas vForum Online June 28th - Tons of great Sessions and Hands-on Labs appeared first on VMware Hands-On Lab (HOL) Blog.

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Congratulations Brian W – DJI Drone Raffle Contest Winner

Folks,

Thank you for participating in our Raffle Drawing for the very cool DJI Drone - we had a lot of fun putting it together for you. We thought it would be great to get to know our winner and did a little write up to introduce him to our readers.

Tell us about your professional career background and interests ?

I work in healthcare specializing in virtualization technology and strategy. I&#rsquo;ve been working in IT for over 20 years, and working with VMware solutions for over 15. My current interests involve Cloud Management and Automation, and Network Virtualization. I also enjoy attending my local VMUG meetings to understand how other people are addressing problems in Healthcare with technology.

How was your Hands-on Lab Experience? Anything we can do to improve the experience?

I&#rsquo;m a huge proponent of the HOL&#rsquo;s. I used them frequently to study for VMware Certification exams, especially to get to bits that aren&#rsquo;t generally available… Additionally, many of the labs give you free reign to go off of the lab manual, and do other tasks. For me, this is much easier than a home lab. Everything is properly configured, consistent, and there&#rsquo;s no consequence for making changes that would break a home lab configuration. Over the years, the HOL environment has gotten better and the catalog broader, there&#rsquo;s really nothing else like it out there.

Advice to users out there on using the Hands-on Labs

Get out there and try them! Don&#rsquo;t be afraid to use a HOL environment for other tasks than the lab, such as performing tasks on a certification blueprint. I rarely find that there are things I cannot perform in the HOL&#rsquo;s, short of complex multisite configurations. The HOL&#rsquo;s are great training if you&#rsquo;re lacking budget, offering the latest content and products.

The post Congratulations Brian W - DJI Drone Raffle Contest Winner appeared first on VMware Hands-On Lab (HOL) Blog.

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New Hands-on Labs and Chance to win a DJI Mavic Pro Drone

New Hands-on Labs released and chance to win a cool DJI Drone

Folks,

We are incredibly happy to announce our latest release of Hands-on Labs and a very cool DJI Drone Raffle Giveaway for taking any of our eligible Hands-on Labs. Please visit our official contest site for more details Contest runs from April 19th to May 19th 2017 Giveaway is forUS residents only, sorry no VMware employees.

Below is a list of our recently released Hands-on Labs for our Spring Release. We would also like to thankour entire team for making this happen. You can take any of these labs from our Hands-on Labs site http://labs.hol.vmware.com

Newly released Hands-on Labs

      • HOL-1731-SDC-1 – What&#rsquo;s New: Virtual SAN v6.5
      • HOL-1731-SDC-2 – Advanced vSAN 6.5: Operations
      • HOL-1733 – What&#rsquo;s New: vRealize Automation v7.2
      • HOL-1810-01-SDC – Virtualization 101: Introduction to vSphere

Updates to existing Hands-on Labs

      • HOL-1701 (all lab codes) – Updated to vROps v6.5 and Log Insight v4. Includes updates to VOA Hands-on Labs
      • HOL-1706-SDC-5 - VMware Cloud Foundation
      • HOL-1710 – Updating to the GA release of vSphere v6.5. Log Insight content
      • HOL-1728-SDC-1 –General updates
      • HOL-1730-USE-1 – Updated to Cloud Native GA code
      • HOL-1751-MBL-1 – New module to include Instant Clones
      • HOL-1756-MBL-1 – New interactive simulation lab and renamed to Horizon Cloud-Hosted Infrastructure - Explore and Manage
      • HOL-1757 Updated to AirWatch v9.0
      • HOL-1787-USE-1 – New features of vCD
      • HOL-1790-CHG-1 – Updated for vRA 7.2

Thank you for your support and enjoy your Hands-on Labs -

VMware Hands-on Labs Team

 

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HOL Three-Tier Application, Part 5 – Use Cases

If you have been following along in this series, first of all, thank you! Next, you should have a basicthree-tier application created:

A Simple Three-Tier Application

I tried to usesimple components to make it usable in either a home lab or a nested environment, so theyshould perform exceedingly wellin areal environment.

Virtual Machine Profile

The component Photon OS machines boot in a few seconds, even in our nested environment, and their profiles are fairly conservative:

  • 1 vCPU
  • 2 GB RAM
  • 15.625 GB disk

Once configured as indicated in this series, theseVMs will export as OVAs that are around 300 MB each, making them reasonably portable.

The storage consumed after thin-provisioned deployment is less than 650 MB for each virtual machine. At runtime, each consumes an additional 2 GB for the swapfile. During boot, in my environment, each VM’sCPU usage is a little over 600 MHz and the active RAM reports 125 MB, but those normalize quickly to nearly 0 MHz and 20 MB active RAM (+23 MB virtualization overhead). You may be able to reduce their RAM allocations, but I have not tried this.

So, what can I do with this thing?

It is nice to have tools, but without a reason to use them, they’re not that much fun. We use tools like this in our labs to demonstrate various functionality of our products and help our users understand how they work. Here are a few ideas, just to get you thinking:

vMotion, Storage vMotion, SRM Protection and Recovery

The virtual machines that you created can be used as a set, butthe base Photon OS template also makes a great single VM for demonstrating vMotion or Site Recovery Manager (SRM)recovery in a lab environment. They are small, but they have some “big VM” characteristics:

  • The VMware Tools provide appropriate information up to vCenter
  • They respond properly to Guest OS restart andpower off actions
  • Photon OS handles Guest Customization properly, so you can have the IP address changed during template deployment andSRM recovery.
  • You can ping and SSH into them
  • You can use them to generate load on your hosts and demonstrate Distributed Resource Scheduler (DRS) functionality

Firewalling/Micro-segmentation

We use a previous version of this application in several of our NSX labs that debuted at VMworld 2016. For a good micro-segmentation use case, you can look atHOL-1703-USE-2 - VMware NSX: Distributed Firewall with Micro-Segmentation. The manual is available for download here, or you can take the lab here.

For a more complicated use case using a similarapplication to demonstrateSRM and NSX integration, look atHOL-1725-USE-2 - VMware NSX Multi-Site DR with SRM.For that lab, the manual is available here and the lab ishere.

Each of the tiers must communicate with the others using specific ports

  • Client to Web = 443/tcp
  • Web to App = 8443/tcp
  • App to DB = 80/tcp

You can use this application to test firewall rules or other network restrictions that you are planning to implement. If a restriction breaks the application, you can determine where and why, then try again. If you want to change the port numbers to match your needs, you can do that as well. Keeping the application simple means that modifications should also be simple.

Load Balancing (Distribution)

The basic idea here is that you can create clones of the web-01a machine as many times as you like and pool them behind a load balancer. In your lab, if you have it, you may want to use NSX as a load balancer. If you want to do that, I suggest checking outModule 3 -Edge Services Gatewayinthe HOL-1703-SDC-1 - VMware NSX: Introduction and Feature Tour lab, which covers how to set that up. The manual is here and the lab is here.

If you want to use another vendor’s solution, feel free to do that as well. This application is REALLY simple. Some free load balancing solutions can be implementedusing nginx or haproxy. Fortunately, we already know about nginx from the build of our web servers, so I will cover that later in this post.First, though, I want to cover a DNS round robin configurationsince understandingthat makes the nginx load balancing simpler for the lab.

Example 1 - Load Distribution via DNS Round Robin

If you don’t have the resources for another VM, you canimplementsimple load distribution viaDNS round robinas long as you understand a few limitations:

  1. You must have access to change DNS for your lab environment.
  2. Using only DNS, you get loaddistribution but not reallybalancing; there is no awareness of theload onany particular node. Rather, you simply get the next one in the list.
  3. There is no awareness of the availability of any node in the pool. DNS simply provides the next address, whether it is responding or not.
  4. Connecting from a single client maynot show balancing since optimizations in modern web browsers maykeep existing sockets open.

In this first example, I have 3 web servers (web-01a, web-02a, web-03a) with IP addresses 192.168.120.30, 31, and 32. My SSL certificate contains the name webapp.corp.local and it is loaded onto each of the web servers.The picture looks something like this:

Create the VMs

To create web-02a and web-03a, I simply clone my web-01aVMthenreset thehostnames and IP addresses of each clone to the new values:

  • web-02a - 192.168.120.31
  • web-03a - 192.168.120.32

Alternatively, I can make a template from the web-01a VM and deploy the copies using Guest Customization to reconfigure them. Just make sure to populate the /etc/hosts file on the customized machines since the process wipes out and rebuilds that file.

Configure DNS

The required DNS changesare not complicated. You basically assign the name webapp.corp.localto the IP addresses of your web servers and set the time-to-live (TTL) to a low, non-zero value.

Using PowerShell against my lab DNS server called controlcenter.corp.localthat manages the corp.localzone, I add DNS records with a 1 second TTL, associatingall of the web server IP addresses to the name webapp.corp.local:

$ttl = New-TimeSpan -Seconds 1Add-DnsServerResourceRecordA -ComputerName 'controlcenter.corp.local' -ZoneName 'corp.local' -name 'webapp' -IPv4Address '192.168.120.30' -TimeToLive $ttlAdd-DnsServerResourceRecordA -ComputerName 'controlcenter.corp.local' -ZoneName 'corp.local' -name 'webapp' -IPv4Address '192.168.120.31' -TimeToLive $ttlAdd-DnsServerResourceRecordA -ComputerName 'controlcenter.corp.local' -ZoneName 'corp.local' -name 'webapp' -IPv4Address '192.168.120.32' -TimeToLive $ttl

If you use a BIND DNS server, just create multiple A records pointing to the same name. BIND 4.9 or higher will automaticallyrotate through the records.In my case, I have a Windows 2012DNS server, and it cycles through the addresses when the webapp.corp.local name is requested.

Testing the Rotation

Here is a simple example of what this looks like from an ESXi host in my lab.A simple ping test shows therotation occurring as intended:

[root@esx-03a:~] ping -c 1 webapp.corp.localPING webapp.corp.local (192.168.120.30): 56 data bytes64 bytes from 192.168.120.30: icmp_seq=0 ttl=64 time=1.105 ms--- webapp.corp.local ping statistics ---1 packets transmitted, 1 packets received, 0% packet lossround-trip min/avg/max = 1.105/1.105/1.105 ms[root@esx-03a:~] ping -c 1 webapp.corp.localPING webapp.corp.local (192.168.120.32): 56 data bytes64 bytes from 192.168.120.32: icmp_seq=0 ttl=64 time=1.142 ms--- webapp.corp.local ping statistics ---1 packets transmitted, 1 packets received, 0% packet lossround-trip min/avg/max = 1.142/1.142/1.142 ms[root@esx-03a:~] ping -c 1 webapp.corp.localPING webapp.corp.local (192.168.120.31): 56 data bytes64 bytes from 192.168.120.31: icmp_seq=0 ttl=64 time=1.083 ms--- webapp.corp.local ping statistics ---1 packets transmitted, 1 packets received, 0% packet lossround-trip min/avg/max = 1.083/1.083/1.083 ms

Accessing the Application

Use the https://webapp.corp.local/cgi-bin/app.py URL from your web browser to access the application. Within the three-tier application, thescript on the app server displays which web server made the call to the application.

The scriptwill show the IP address of the calling web server unless it knows the name you would like it to display instead. You provide amapping of the IPs to the names you would like displayed at the top of the app.py script on the app server:

webservers = { '192.168.120.30':'web-01a', '192.168.120.31':'web-02a', '192.168.120.32':'web-03a'}

Simply follow the syntax and replace or add the values which are appropriate for your environment.

A Challenge ShowingLoad Distribution froma Single Host

Hmm… while the ping test shows that DNS is doing what we want, clicking the Refreshbutton in your web browser maynot be switching to a different web server as you expect.

Arefresh does not necessarily trigger a new connection and DNS lookup, even if the TTL has expired. Modern web browsers implement optimizations that will keep an existing connectionopen because odds are good that you will want to request more data from the same site.If a connection is already open, the browser will continue to use that, even if the DNS TTLhas expired. This means that you will not connectto a different web server.

You can wait for the idle sockets to time out or force the sockets closed and clear the web browser’s internal DNS cache before refreshing the web page, but that is not really convenientto do every time you want to demonstrate the distribution functionality. If you want to be able to click Refresh and immediately see that you have connected to a different web server in the pool, you can use NSX or a third-party load balancer. If you want to use the tools that we have currently available, the next example works around this issue.

Example 2 - Implementing a (Really)BasicLoad Balancer

Making a small change to the nginx configuration on one of the web server machines and adjusting DNS can provide a simple demonstration load balancer for your lab. This requires a slight deviation fromour current architecture to inject the load balancer VM in front of the web server pool:

Three-Tier Application with Load Balancer

Note that there are better, more feature-rich ways to do this, but we are going for quick and simple in the lab.

Create the Load Balancer

Create the load balancer VM. You can deploy a new one from a Photon OS base template and go through the configuration from there, but conveniently, the difference between the load balancer configuration and that of our web servers is just one line!

So, make a copy of the web-01a VM and updateits address and hostname:

  • lb-01a - 192.168.120.29

Change the nginx Configuration

On the lb-01a VM, edit the /etc/nginx/nginx.conf file

# vi +130 /etc/nginx/nginx.conf

Changeline 130 from

proxy_pass https://app-01a.corp.local:8443/;

to

proxy_pass https://webpool.corp.local/;

This will allow us to leverage DNS round-robin to rotate through the list of web servers and distribute the load. Nginx has advanced configurations to handle load balancing, but this will get the job done for a lab or demonstration. Terminating SSL on the load balancer while using plain HTTP on the web servers allows a lot more flexibility, but the configuration changes are beyond the scope of what I want to dohere.

Restart nginx

# systemctl restart nginx

Adjust DNS

Finally, adjust DNS to move the webapp.corp.local name to point at the load balancer and put the web servers into webpool.corp.localinstead.

If you are using Windows DNS, you can use PowerShell. For BIND, edit and create the records as needed.

  1. Remove the existing webapp.corp.local pool by deleting all of the A records that point to the individual web servers:
$rec = Get-DnsServerResourceRecord -ComputerName 'controlcenter.corp.local' -ZoneName 'corp.local' -Name 'webapp' -RRType Aif( $rec ) {   $rec | % { Remove-DnsServerResourceRecord -InputObject $_ -ZoneName 'corp.local' -Force }}

2. Create a newwebapp.corp.localA record that points to the lb-01a machine:

Add-DnsServerResourceRecordA -ComputerName 'controlcenter.corp.local' -ZoneName 'corp.local' -name 'webapp' -IPv4Address '192.168.120.29'

3. Create the newwebpool.corp.local that contains the individual web servers:

$ttl = New-TimeSpan -Seconds 1Add-DnsServerResourceRecordA -ComputerName 'controlcenter.corp.local' -ZoneName 'corp.local' -name 'webpool' -IPv4Address '192.168.120.30' -TimeToLive $ttlAdd-DnsServerResourceRecordA -ComputerName 'controlcenter.corp.local' -ZoneName 'corp.local' -name 'webpool' -IPv4Address '192.168.120.31' -TimeToLive $ttlAdd-DnsServerResourceRecordA -ComputerName 'controlcenter.corp.local' -ZoneName 'corp.local' -name 'webpool' -IPv4Address '192.168.120.32' -TimeToLive $ttl

Access the Application

Now, point your web browser to the https://webapp.corp.local/cgi-bin/app.py URL. Each timeyou click Refresh in your web browser or enter a new search string in the Name Filter box and click the Apply button, the data refreshand the Accessed via:line should update with a different web server from the pool:

Rotating through web servers in the pool

Because the web browser’s connection is to the load balancer VM, which controls which web server receives the request, we eliminate the issue experienced when using only DNS round robin. This very basic implementation does not handle failed servers in the pool and is not something thatwould be used in production, but, hey, this is a lab!

It is possible to extend this idea to put a load balancer in front of a pool of application servers as well:replace line 130 in eachweb server’s /etc/nginx/nginx.conf file with the URL of anapp server pool instead of pointing them directly at theapp-01a VM.

That’s a Wrap!

That concludes the series on building a minimal three-tier application. I am hopeful that you have found this interesting and can use these tools in your own environment.

Thank you for reading!

The post HOL Three-Tier Application, Part 5 – Use Cases appeared first on VMware Hands-On Lab (HOL) Blog.

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VMware Hands-on Labs over 1 Million Labs Served – Thank You

Folks

We are incredibly proud of announcing that we have delivered over 1 Million Hands-on Labs to 269K active users since January 1st 2013. We really appreciate the help we have received from all of the teams involved for making this happen.

Some Fun Facts:

  • Users on average spend 51 minutestaking a Lab, taking 3.7 Labs
  • We deliver 1200 - 1800 Labs per day
  • We have over 70 Labs and 400 Lab Modules for you take
  • We move more than 32 TB of Data per cloud - During VMworld we usually run 9 Clouds

Looking forward to a great 2017

This year will be the year of SAS Hands-on Labs supporting recent AWS announcements that will be releasedfor VMworld 2017, and our Global vForums.

We have consistently added users over the years at VMworld, our launching pad for new Hands-on Labs and looking forward to expanding our global footprint.

Thanks for your support and looking forward to a great 2017 !

The post VMware Hands-on Labs over 1 Million Labs Served - Thank You appeared first on VMware Hands-On Lab (HOL) Blog.

Read more..

VMware Hands-on Labs over 1 Million Labs Served – Thank You

Folks

We are incredibly proud of announcing that we have delivered over 1 Million Hands-on Labs to 269K active users since January 1st 2013. We really appreciate the help we have received from all of the teams involved for making this happen.

Some Fun Facts:

  • Users on average spend 51 minutestaking a Lab, taking 3.7 Labs
  • We deliver 1200 - 1800 Labs per day
  • We have over 70 Labs and 400 Lab Modules for you take
  • We move more than 32 TB of Data per cloud - During VMworld we usually run 9 Clouds

Looking forward to a great 2017

This year will be the year of SAS Hands-on Labs supporting recent AWS announcements that will be releasedfor VMworld 2017, and our Global vForums.

We have consistently added users over the years at VMworld, our launching pad for new Hands-on Labs and looking forward to expanding our global footprint.

Thanks for your support and looking forward to a great 2017 !

The post VMware Hands-on Labs over 1 Million Labs Served - Thank You appeared first on VMware Hands-On Lab (HOL) Blog.

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HOL Three-Tier Application, Part 3 – App Server

This is the thirdpost in the series about building a three-tier application for demonstration, lab, and education purposes. At this point, you have downloaded Photon OS and prepared the base template according to the specifications and have built and tested the database server, db-01a.

Workingfrom thebottom-up, we move to the application server, which sits between the database and the web tier. As with the database, this is nothing fancy, but it gets the job done.

The Application Server(app-01a)

The application server sits in the middle of our stack and handles the formatting of data that is returned from the database. We will again use Apache and Python because we know how to use those tools from the database server build. This time, the CGI script presents an HTML form and table containingdata pulled from the database via HTTP.

To add a bit of realism and fun to the process, we will configure SSL on the application server. The basic configuration is pretty simple once you have the certificate and key, and it is good to know how to do. Sure, we will be usingour own self-signed certificate, but this is a lab!

The red box in the following diagram highlightsthe component that we are building in this post.

Note that the first steps look quite a bit like the steps we performed for the database server. I’ll outline them here. Details can be found in my previouspost.Let&#rsquo;s get started!

  1. Deploy a copy of the base Photon template you created by following the steps in my first post. Name it something that makes sense to you for your app server. I called mine app-01a
  2. Power it up and log in as the root user
  3. Changethe hostname in /etc/hostnameand in /etc/hosts
  4. Changethe IP address in/etc/systemd/network/10-static-eth0.network
  5. Use a SSHclient to access the machine as root (this makes pasting commands easier)
  6. Install the Apache web server

Install the Apache server here, just like on the database server

# tdnf install httpd

Due to the SSL requirement on this machine, there are more files to edit than in the database server build, so get your editor ready!

Prepare to create the certificate and key

Creating the certificate is easiest if we pass it a file containing all of the answers needed by openssl.Navigate to /tmp and create the file app-01a.conf

# cd /tmp# vi app-01a.conf

Put the following contents into the file. Substitute values appropriate for your environment. The CN and the values under the [alt_names] section are the most important for our purposes here.

[req]distinguished_name = req_distinguished_namex509_extensions = v3_reqprompt = no[req_distinguished_name]C = USST = CaliforniaL = Palo AltoO = VMwareOU = Hands-on LabsCN = app-01a.corp.local[v3_req]keyUsage = keyEncipherment, dataEnciphermentextendedKeyUsage = serverAuthsubjectAltName = @alt_names[alt_names]DNS.1 = app-01a.corp.localDNS.2 = app-01aIP.1 = 192.168.120.20

Save and close the file.

Generate the key and certificate from the configuration file

Note that this is a long command. You may need to scroll all the way to the right to get all of it.

# openssl req -x509 -nodes -days 1825 -newkey rsa:2048 -keyout app.key -out app.pem -config app-01a.conf

(optional) Validate that the PEM file “looks right”

# openssl x509 -in app.pem -noout -text

Read through the text output and make sure the certificate looks as you expect. If you filled out the configuration file properly, it should be fine.

Leave those files where they are for now. We’ll need them in a few minutes.

Configure the web server to run SSL on port 8443

SSL over the default port is so yesterday. Besides, we want something that differentiates this traffic from the port 443 SSL traffic that comesfrom the client to the web server. Changing the portmakes the firewall rules more interesting and easier to distinguish. Besides, this is not normally user-facing, so there is no complexity with requiring normal usersto append“:8443” to the end of the host portion of the URL.

Openthe configuration file

Use the “+52” to jump to the line we want.

# vi +52 /etc/httpd/httpd.conf

Disable listening on port 80

We don’t need this server listening on the default HTTP port, so put a # in front of the “Listen 80” on line 52)

#Listen 80

Load the SSL module

Is this thing on? We need to turn on the SSL functionality, which is disabled in the default configuration. Uncomment (remove the # from the beginning of) line 143:

LoadModule ssl_module /usr/lib/httpd/modules/mod_ssl.so

Load the CGI module

Just like on the database server, we have to enable the CGI module. Add the following text on its own line at the end of the module loading, above the text. I use line 176.

LoadModule cgi_module /usr/lib/httpd/modules/mod_cgi.so

Include the SSL configuration file

Near the bottom of the file (around line 508), un-comment the line

Include conf/extra/httpd-ssl.conf

Save the file and exit.

Configure SSL Settings

Open the SSL “extra settings” file.

# vi +36 /etc/httpd/conf/extra/httpd-ssl.conf

Online 36, locate the Listen line and change the port number from 443 to 8443

Listen 8443

To make things work, I also had to comment out line 92:

#SSLSessionCache "shmcb:/etc/httpd/logs/ssl_scache(512000)"

Change the virtual host’s port number from 443 to 8443 on line 121

On lines 144 and 154, ensure that the following are set (these should be the defaults) andnote the paths:

SSLCertificateFile "/etc/httpd/conf/server.crt"SSLCertificateKeyFile "/etc/httpd/conf/server.key"

Put thecertificates in the rightplace

Remember the files you created at the beginning? Now is the time to move themto where they are expected. Just overwrite anythingis already there.

# mv /tmp/app.key /etc/httpd/conf/server.key# mv /tmp/app.pem /etc/httpd/conf/server.crt

Start the web server and set it to startup when the VM boots

# systemctl start httpd# systemctl enable httpd

Everything should start up cleanly. If not, you may have a typo somewhere. The following command provides some good information to help locate the issue:

# systemctl status -l httpd.service

Once you have the web server startedproperly, take a little break. Now is just the configuration part.

Create the Python script that is our “application”

As I have written previously, Python is not my native language, but it isalready there and I can convince it to do what I need. This CGI script takes the text data off the HTTP connection fromthe database server and formats it. It also has a simple filter field and button to change the data view a bit. Each button click submits a new request to the database and shows that the connection is still possible.

I have added some complexity here because it can provide useful information in some demonstration cases. If the IP address of the source webserver is in the webservers table, its name will be displayed. Otherwise, the IP address is used when the Accessed via:line is printed. In certain situations, this can be useful for demonstratingthat load balancing is working.

Create the script

# vi/etc/httpd/cgi-bin/app.py

Add the following contents to app.py, remembering that spacing is important:

#!/usr/bin/env pythonimport os, sys, cgiimport requestswebservers = {  '192.168.120.30':'web-01a',  '192.168.120.31':'web-02a',  '192.168.120.32':'web-03a' }print "Content-type:text/htmlnn";print "Customer Databasen"print "n"print "

Customer Database Access

n"remote = os.getenv("REMOTE_ADDR")form = cgi.FieldStorage()querystring = form.getvalue("querystring")if remote in webservers : accessName = webservers[remote]else : accessName = remoteprint "Accessed via:",accessName,"n

"if querystring != None: url = 'http://db-01a.corp.local/cgi-bin/data.py?querystring=' + querystringelse: url = 'http://db-01a.corp.local/cgi-bin/data.py' querystring = ""r = requests.get(url)print '

'print ' Name Filter (blank for all records):'print ' 'print ' 'print '
'print "n"print "n"#deal with the data coming across the wirea = r.text.split("|n#")for row in a: if len(row) != 1: print "" splitrow = row.split("|") for item in splitrow: if item != None: print "" print "n" print "n"

Save and close the file.

Set execute permissions

# chmod 755 /etc/httpd/cgi-bin/app.py

Verify

Now, as long as your database server is online and reachable, accessingthe script via https on port 8443, will producethe data formatted as HTML:

# curl -k https://app-01a:8443/cgi-bin/app.py

If you access itvia a graphical browser like Chrome or Firefox, you can and witness the fruits of your labors thus far. Note that you will have to accept the self-signed certificate, at least temporarily. The -k switch to curl tells it to ignore the untrusted SSL certificate and continue in “insecure” mode.

Here is what it looks like from Chrome. I used the IP address in the URL here becauseI have not created a DNS entry for app-01a. My plan is to provide access to this application only via the web front-end and I am only accessing the app server directly as part of the build.

The good news is that we are almost finished with the application. As you can see, you can use this as it stands as a “two-tier application” by creating a DNS record for the app-01a server, but I promised youthree tiers. Stick with me. We will get there in the next post.

Thanks for reading!

The post HOL Three-Tier Application, Part 3 - App Server appeared first on VMware Hands-On Lab (HOL) Blog.

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HOL Three-Tier Application, Part 2 – DB server

This is the second post in the series about building a three-tier application for demonstration, lab, and education purposes. At this point, you have downloaded Photon OS and prepared the base template according to the specifications. If not, please go to the first post in the series to prepare your environment.

I am tryingto release these posts on Wednesdays, but yesterday was a holiday in the US, so I had some time to get this one out the door early.

For the build, I will work bottom-up so it is possible totest the components as we go along andaddress any issues before we get to the end and have to worry aboutthe whole stack.

The Database (db-01a)

There are many choices that could have been made here, but I wanted to minimize the steps required and use the tools I had available by default, wherever possible. So, the database server for this application uses a SQLite database. This may seem like an odd choice since ithas no native remote access. But, the sqlite3is already present on thePhoton image.So is Python. Don’t expect elegance here since I do not normally use Python.I hacked together a simple CGI scriptto query the database and send the results over HTTP. It is not fancy, but it is small and does just enough for my needs.

Fear not! SQLite is simple enough that you don’t need any kind of DBA skills to use it. The minimal SQL that I know was enough to get this done.

The red box in the following diagram highlightsthe component that we are building in this post.

Let’s get started!

Deploy a copy of the base template

Deploy a copy of the base Photon template you created by following the steps in myfirst post. Name it something that makes sense to you. I called mine db-01a.

Power it up and log in as the root user.

Set theIP address

You need to configure the IP address for this machine. Here are the contents of my/etc/systemd/network/10-static-eth0.network file.

[Match]Name=eth0[Network]Address=192.168.120.10/24Gateway=192.168.120.1DNS=192.168.110.10Domains=corp.local

Set the name

Update the name in the/etc/hostsand/etc/hostname files with the proper name for this VM. Replace every occurrence of the name you used in the template with the name of this VM. Note that the hostname withinthe prompt string will change whenyou log out.

Restart the network to apply the settings

# systemctl restart systemd-networkd

Once you have finished with these steps, make sure you can access the network before moving on. You need Internet access in order to proceed.

SSH in

At this point, I strongly suggest you SSH tothe machine so that you can paste text. Doing all of the work from the console is possible, but pasting is easier. So, fire up puTTY or whatever else you use as your preferred SSH client.

Install the web server

I am using Apache here since I can get the base install to do what I need in pretty short order. Unfortunately, it is not already present, so we need to install it. Fortunately, it only takes a few minutes:

# tdnf install httpd

Make a directory to store the database file and make apache the owner

So you don’t absolutely needto do this, but I sometimes like to separate my data from the executables.

# mkdir /etc/httpd/db# chown apache:apache /etc/httpd/db

Start the web server and set it to startup when the VM boots

# systemctl start httpd# systemctl enable httpd

Create the database’s front-end CGI script

There is not much to this one. It performs a simple query of the database and dumps the result. You can type in the code, but if you have connected via SSH, you canpaste it in. I recommend the latter. Keep in mind that Python uses whitespace to give the program structure, so indenting is important. More precisely,the exact amount of indentation does not matter, but the relative indentation of nested blocks to one another matters a lot. If that sounds confusing, just make sure the spacing looks like mine.

This script takes an optional parameter named queryval that allows the data to be filtered on the name property of the records. It is a step above the “dump everything” approach we used in previous versions and provides the possibility for some user interaction.

Open anew file,/etc/httpd/cgi-bin/data.py

#!/usr/bin/env pythonimport cgiimport sqlite3conn=sqlite3.connect('/etc/httpd/db/clients.db')curs=conn.cursor()print "Content-type:text/plainnn";form = cgi.FieldStorage()querystring = form.getvalue("querystring")if querystring != None:   queryval = "%" + querystring + "%"   select = "SELECT * FROM clients WHERE name LIKE '" + queryval + "'"else:   select = "SELECT * FROM clients"for row in curs.execute(select):   if len(row) == 4:      for item in row:        print item,'|'      print "#"conn.close()

Save and close the file, then mark it executable

# chmod 755 /etc/httpd/cgi-bin/data.py

Create the database file and load it with data

SQLite will create the file if it is not already present. Bonus!

# sqlite3 /etc/httpd/db/clients.db

At the sqlite> prompt, create the table:

CREATE TABLE 'clients' ( "Rank" integer, "Name" varchar(30), "Universe" varchar(25), "Revenue" varchar(20) );

Then, load in some data. Feel free to use whatever you like:

INSERT INTO 'clients' VALUES (1,'CHOAM','Dune','$1.7 trillion'), (2,'Acme Corp.','Looney Tunes','$348.7 billion'), (3,'Sirius Cybernetics Corp.',"Hitchhiker's Guide",'$327.2 billion'), (4,'Buy n Large','Wall-E','$291.8 billion'), (5,'Aperture Science, Inc.','Valve','$163.4 billion'), (6,'SPECTRE','007','$157.1 billion'), (7,'Very Big Corp. of America','Monty Python','$146.6 billion'), (8,'Frobozz Magic Co.','Zork','$112.9 billion'), (9,'Warbucks Industries',"Lil' Orphan Annie",'$61.5 billion'), (10,'Tyrell Corp.','Bladerunner','$59.4 billion'), (11,'Wayne Enterprises','Batman','$31.3 billion'), (12,'Virtucon','Austin Powers','$24.9 billion'), (13,'Globex','The Simpsons','$23.7 billion'), (14,'Umbrella Corp.','Resident Evil','$22.6 billion'), (15,'Wonka Industries','Charlie and the Chocolate Factory','$21.0 billion'), (16,'Stark Industries','Iron Man','$20.3 billion'), (17,'Clampett Oil','Beverly Hillbillies','$18.1 billion'), (18,'Oceanic Airlines','Lost','$7.8 billion'), (19,'Brawndo','Idiocracy','$5.8 billion'), (20,'Cyberdyne Systems Corp.','Terminator','$5.5 billion'), (21,'Paper Street Soap Company','Fight Club','$5.0 billion'), (22,'Gringotts','Harry Potter','$4.4 billion'), (23,'Oscorp','Spider-Man','$3.1 billion'), (24,'Nakatomi Trading Corp.','Die-Hard','$2.5 billion'), (25,'Los Pollos Hermanos','Breaking Bad','$1.3 billion');

Once you are happy with the data you have entered — ensure that you finish with a semi-colon and a newline— press Control-D to close the sqlite session.

Set the database file’s owner

The apache user running the web server needs access to this file in order for the CGI script to read the data.

# chown apache:apache /etc/httpd/db/clients.db

Enable CGI on the webserver

The default Apache install on Photon does not have the CGI module loadedby default. It is simple enough to turn it on:

Open the web server’s configuration file. The +176before the file name opens the file at line 176, which is where we want to start:

# vi +176 /etc/httpd/httpd.conf

At line 176, add the following line to load the CGI module:

LoadModule cgi_module /usr/lib/httpd/modules/mod_cgi.so

Atline 379, add the following to enableaccess to the database directory. It goes right before a line that starts with

#database directory    AllowOverride None    Options None    Require all granted

Save and close the file.

Restart the web server to read the updated configuration

# systemctl restart httpd

Verify

Now, if you access the script via http, you should see the data.

# curl http://db-01a/cgi-bin/data.py

It won’t look too pretty, but the user never sees this back end data. That’s where the application server comes in. At this point, the resultshould look something like this:

root@db-01a [ ~ ]# curl http://db-01a/cgi-bin/data.py1 |CHOAM |Dune |$1.7 trillion |#... (truncated) ...#24 |Nakatomi Trading Corp. |Die-Hard |$2.5 billion |#25 |Los Pollos Hermanos |Breaking Bad |$1.3 billion |#root@db-01a [ ~ ]#

The next piece of the puzzle is the application server, which consumes the data provided by this component. If you had no problems with this setup, the rest should be a breeze. This is the most complicated part of the whole thing.

Thank you for reading!

The post HOL Three-Tier Application, Part 2 - DB server appeared first on VMware Hands-On Lab (HOL) Blog.

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