(Last Updated On: May 11, 2019)

1. Introduction

Setting up and managing our own servers can take a considerable amount of time especially if we are not a day to day linux user. That is why we see things like serverless and containers catching on. There’s another option out there though too and it’s called unikernels.

What are unikernels though? Unikernels are simple single application operating systems. Instead of deploying our software on top of linux unikernels create an operating system out of our application and run only that app – nothing else. There’s no concept of usernames/passwords or sshin’g into the application as it is only running one application. Traditionally unikernels have been hard to work with as they used to require expert level of systems knowledge. Now there are newer tools like OPS that fix that.

2. Setup

In the next few minutes we are going to build, run, then deploy a php unikernel. First things first let’s download OPS from https://ops.city:

curl https://ops.city/get.sh -sSfL | sh

We can also download and build it from github. can always go to https://github.com/nanovms/ops and build it from source – it’s written in Go.

3. Build and Run our First PHP Unikernel

Now that we have that let’s create a temporary working directory:

mkdir p && cd p

For this simple example we’ll just use the built-in php webserver just to keep things simple. Put this into a config.json file:

{ "Args":["-S", "0.0.0.0:3030"], "Files": ["index.php"] }

What this does is tell the built in php webserver to listen on port 3030 and place the index.php file onto the otherwise barren filesystem. We’ll put this into a index.php:

<?php echo 'hello from php!'; ?>

Now let’s run it via:

ops load php_7.2.13 -c config.json -p 3030

Here we tell OPS that we wish to use PHP7. When we are running this it will first download a php package then it looks at the config file and finally opens up a local port on 3030.

We should see this:

[php -S 0.0.0.0:3030] booting /Users/eyberg/.ops/images/php.img ... assigned: 10.0.2.15

Assuming that boots we should now be able to hit it with curl:

➜ ~ curl -XGET http://127.0.0.1:3030/ hello from php!% ➜ ~ curl -XGET http://127.0.0.1:3030/ hello from php!%

4. Deploy to Google Cloud

Great! We just ran our first php unikernel! Now let’s deploy it. Assume have a google cloud account we’ll need a project id, a service worker key, and a cloud storage bucket to place our built images in. We definitely don’t have to use google but we are using it for this example.

We are going to slightly modify our config.json file and put this inside:

{ "Args":["-S", "0.0.0.0:80"], "Files": ["index.php"], "CloudConfig" :{ "ProjectID" :"my-project-id", "BucketName":"my-bucket" }, "RunConfig" : {"Memory": "2G"} }

What this does is tell OPS to place our built image in the bucket ‘my-bucket’ and use ‘my-project-id’. We also changed the port to 80 which is the default HTTP port.

If we got a service worker key we can put that somewhere to source like so:

export GOOGLE_APPLICATION_CREDENTIALS=~/gcloud.json

Then let’s build the image. What this does is create a virtual machine on Google Cloud that contains only our application with the php interpreter. It’s important to note that there is no underlying linux system here. When the virtual machine boots it boots straight into our application just like it did locally. This make it run much faster and safer than linux.

➜ p ops image create -c config.json -p php_7.2.13 [php -S 0.0.0.0:80] bucket found: nanos-deploy Image creation started. Monitoring operation operation-1556904873950-587ff29f5fcc5-76e6bf08-ff926925. .............. Operation operation-1556904873950-587ff29f5fcc5-76e6bf08-ff926925 completed successfullly. Image creation succeeded nanos-php-image. gcp image 'nanos-php-image' created...

We should see something like this when it’s done building:

➜ p ops image list +--------------------+--------+-------------------------------+ | NAME | STATUS | CREATED | +--------------------+--------+-------------------------------+ | nanos-main-image | READY | 2019-03-21T15:06:17.567-07:00 | +--------------------+--------+-------------------------------+ | nanos-node-image | READY | 2019-04-16T23:16:03.145-07:00 | +--------------------+--------+-------------------------------+ | nanos-php-image | READY | 2019-05-03T10:34:34.966-07:00 | +--------------------+--------+-------------------------------+

Now let’s create an instance. Keep in mind an instance is the server. The image is the actual disk image of the server.

➜ p ops instance create -p prod-1033 -z us-west2-a -i nanos-php-image Instance creation started using image projects/prod-1033/global/images/nanos-php-image. Monitoring operation operation-1556905041207-587ff33ee1f25-fc8382ab-ec299733. ..... Operation operation-1556905041207-587ff33ee1f25-fc8382ab-ec299733 completed successfullly. Instance creation succeeded nanos-php-image-1556905040.

If we look at the instance list we can see it running:

➜ p ops instance list -z us-west2-a -p prod-1033 +----------------------------+---------+-------------------------------+-------------+--------------+ | NAME | STATUS | CREATED | PRIVATE IPS | PUBLIC IPS | +----------------------------+---------+-------------------------------+-------------+--------------+ | nanos-php-image-1556905040 | RUNNING | 2019-05-03T10:37:22.465-07:00 | 10.240.0.48 | 35.236.11.13 | +----------------------------+---------+-------------------------------+-------------+--------------+

Now if we hit that ip up with curl we can see our php unikernel running in Google Cloud!

➜ ~ curl -XGET http://35.236.11.13 hello from php!% ➜ ~ curl -XGET http://35.236.11.13 hello from php!%

We can also see the logs from the unikernel:

➜ p ops instance logs nanos-php-image-1556905040 -p prod-1033 -z us-west2-a SeaBIOS (version 1.8.2-20190322_093631-google) Total RAM Size = 0x0000000080000000 = 2048 MiB CPUs found: 1 Max CPUs supported: 1 found virtio-scsi at 0:3 virtio-scsi vendor='Google' product='PersistentDisk' rev='1' type=0 removable=0 virtio-scsi blksize=512 sectors=2097152 = 1024 MiB drive 0x000f2a30: PCHS=0/0/0 translation=lba LCHS=1024/32/63 s=2097152 Booting from Hard Disk 0... assigned: 10.240.0.48 [Fri May 3 17:39:36 2019] 1.2.3.4:57595 [200]: / [Fri May 3 17:39:37 2019] 1.2.3.4:57596 [200]: / [Fri May 3 17:39:59 2019] 92.112.48.216:35338 [200]: /

5. Conclusion

Congratulations! We’ve built, ran and deployed our first php unikernel on google cloud – now we can go show our friends that we don’t need servers to deploy our applications anymore! Unikernels give us the convenience of containers and serverless with the protection and speed of traditional virtual machines.