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108 lines
4.0 KiB
108 lines
4.0 KiB
# Deploying a Play/Scala-based web application with Ansible
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- Requires Ansible 1.2
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- Expects CentOS/RHEL 6 hosts (64 bit)
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### A Primer into Play Framework
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----------------------------------
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- Play Framework: Play is a pure Java and Scala framework used to develop Web
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Applications, It focuses on developer productivity, modern web and mobile
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applications, and predictable, minimal resource consumption (CPU, memory,
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threads) resulting in highly performant, highly scalable applications, Play
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compiles Java and Scala sources directly and hot-reloads them into the JVM
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without the need to restart the server.
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- Akka: Akka is a toolkit and runtime for building highly concurrent,
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distributed, and fault tolerant event-driven applications on the JVM.
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- Scala: Scala is a general purpose programming language designed to express
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common programming patterns in a concise, elegant, and type-safe way. Scala
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smoothly integrates features of object-oriented and functional languages,
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enabling developers to be more productive while retaining full interoperability
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with Java and taking advantage of modern multicore hardware. Scala makes it
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easy to avoid shared state, so that computation can be readily distributed
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across cores on a multicore server, and across servers in a datacenter. This
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makes Scala an especially good match for modern multicore CPUs and distributed
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cloud-computing workloads that require concurrency and parallelism.
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## Example Deployment using Ansible
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This example deploys a very simple application which takes a hostname as a parameter
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from the user and uses Ansible itself to gather and display facts from that machine.
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It shows how to deploy a simple Play-based app, as well as how to call out to Ansible
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from inside Scala.
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Before running the playbook, modify the inventory file 'hosts' to match your
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environment. Here's an example inventory:
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[webapp_server]
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play_server
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Run the playbook to deploy the app:
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ansible-playbook -i hosts site.yml
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Once the playbooks complete, you can check the deployment by logging into the
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server console at http://<server-ip>:9000/. You should get a page similar to
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image below.
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## Fetching Facts from Hosts
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To use the example webapp and fetch facts from a host, enter the hostname of
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host as shown in the figure above and press submit. Please note that the
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application uses Ansible to gather facts so the hosts should have SSH keys
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set up and the host entry should be available in the Ansible inventory file in
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/etc/ansible/hosts.
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Upon submission, the application should return a valid json consisting the host
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facts:
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localhost | success >> {
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"ansible_facts": {
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"ansible_all_ipv4_addresses": [
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"192.168.2.51"
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],
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"ansible_all_ipv6_addresses": [
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"fe80::5054:ff:fe58:776d"
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],
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"ansible_architecture": "x86_64",
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"ansible_bios_date": "01/01/2007",
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"ansible_bios_version": "0.5.1",
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"ansible_cmdline": {
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"KEYBOARDTYPE": "pc",
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"KEYTABLE": "us",
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"LANG": "en_US.UTF-8",
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"SYSFONT": "latarcyrheb-sun16",
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"quiet": true,
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"rd_NO_DM": true,
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"rd_NO_LUKS": true,
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"rd_NO_LVM": true,
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"rd_NO_MD": true,
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"rhgb": true,
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"ro": true,
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"root": "UUID=5202a2bc-1a30-424f-855b-5d51a3cba8df"
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},
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"ansible_date_time": {
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"date": "2013-05-25",
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"day": "25",
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"epoch": "1369483888",
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"hour": "17",
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"iso8601": "2013-05-25T12:11:28Z",
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"iso8601_micro": "2013-05-25T12:11:28.551538Z",
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"minute": "41",
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"month": "05",
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"second": "28",
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"time": "17:41:28",
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"tz": "IST",
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"year": "2013"
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},
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The facts can also be fetched by making a GET request with following url.
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http://<serverip>:9000/inventoryID?hostname=<hostname>
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