---
title: Preparing our low side
exercise: 2
date: '2023-12-18'
tags: ['openshift','containers','kubernetes','disconnected']
draft: false
authors: ['default']
summary: "Downloading content and tooling for sneaker ops 💾"
---

A disconnected OpenShift installation begins with downloading content and tooling to a prep system that has outbound access to the Internet.  This server resides in an environment commonly referred to as the **Low side** due to its low security profile. 

In this exercise we will be creating a new [AWS ec2 instance](https://aws.amazon.com/ec2) in our **Low side** that we will carry out all our preparation activities on.


## 2.1 - Creating a security group

We'll start by creating an [AWS security group](https://docs.aws.amazon.com/vpc/latest/userguide/vpc-security-groups.html) and collecting its ID. 

We're going to use this shortly for the **Low side** prep system, and later on in the workshop for the **High side** bastion server.

Copy the commands below into your web terminal:

```bash
# Obtain vpc id
VPC_ID=$(aws ec2 describe-vpcs | jq '.Vpcs[] | select(.Tags[].Value=="disco").VpcId' -r)
echo "Virtual private cloud id is: ${VPC_ID}"

# Obtain first public subnet id
PUBLIC_SUBNET=$(aws ec2 describe-subnets | jq '.Subnets[] | select(.Tags[].Value=="Public Subnet - disco").SubnetId' -r)

# Create security group
aws ec2 create-security-group --group-name disco-sg --description disco-sg --vpc-id ${VPC_ID} --tag-specifications "ResourceType=security-group,Tags=[{Key=Name,Value=disco-sg}]"

# Store security group id
SG_ID=$(aws ec2 describe-security-groups --filters "Name=tag:Name,Values=disco-sg" | jq -r '.SecurityGroups[0].GroupId')
echo "Security group id is: ${SG_ID}"
```

<Zoom>
|![workshop](/workshops/static/images/disconnected/security-group.gif)          | 
|:-----------------------------------------------------------------------------:|
| *Creating aws ec2 security group*                                             |
</Zoom>


## 2.2 - Opening ssh port ingress

We will want to login to our soon to be created **Low side** aws ec2 instance remotely via `ssh` so let's enable ingress on port `22` for this security group now:

> Note: We're going to allow traffic from all sources for simplicity (`0.0.0.0/0`), but this is likely to be more restrictive in real world environments:

```bash
aws ec2 authorize-security-group-ingress --group-id $SG_ID --protocol tcp --port 22 --cidr 0.0.0.0/0
```

<Zoom>
|![workshop](/workshops/static/images/disconnected/ssh-port-ingress.gif)          | 
|:-----------------------------------------------------------------------------:|
| *Opening ssh port ingress*                                                    |
</Zoom>


## 2.3 - Create prep system instance

Ready to launch! 🚀 We'll use the `t3.micro` instance type, which offers `1GiB` of RAM and `2` vCPUs, along with a `50GiB` storage volume to ensure we have enough storage for mirrored content:

> Note: As mentioned in [OpenShift documentation](https://access.redhat.com/documentation/en-us/openshift_container_platform/4.14/html/installing/disconnected-installation-mirroring) about 12 GB of storage space is required for OpenShift Container Platform 4.14 release images, or additionally about 358 GB for OpenShift Container Platform 4.14 release images and all OpenShift Container Platform 4.14 Red Hat Operator images.

Run the command below in your web terminal to launch the instance. We will specify an Amazon Machine Image (AMI) to use for our prep system which for this lab will be the [Marketplace AMI for RHEL 8](https://access.redhat.com/solutions/15356#us_east_2) in `us-east-2`.

```bash
aws ec2 run-instances --image-id "ami-092b43193629811af" \
  --count 1 --instance-type t3.micro \
  --key-name disco-key \
  --security-group-ids $SG_ID \
  --subnet-id $PUBLIC_SUBNET \
  --associate-public-ip-address \
  --tag-specifications "ResourceType=instance,Tags=[{Key=Name,Value=disco-prep-system}]" \
  --block-device-mappings "DeviceName=/dev/sdh,Ebs={VolumeSize=50}"
```

<Zoom>
|![workshop](/workshops/static/images/disconnected/launch-prep-ec2.gif)         | 
|:-----------------------------------------------------------------------------:|
| *Launching a prep rhel8 ec2 instance*                                         |
</Zoom>


## 2.4 - Connecting to the low side

Now that our prep system is up, let's `ssh` into it and download the content we'll need to support our install on the **High side**.

Copy the commands below into your web terminal. Let's start by retrieving the IP for the new ec2 instance and then connecting via `ssh`:

> Note: If your `ssh` command times out here, your prep system is likely still booting up. Give it a minute and try again.

```bash
PREP_SYSTEM_IP=$(aws ec2 describe-instances --filters "Name=tag:Name,Values=disco-prep-system" | jq -r '.Reservations[0].Instances[0].PublicIpAddress')
echo $PREP_SYSTEM_IP

ssh -i disco_key ec2-user@$PREP_SYSTEM_IP
```

<Zoom>
|![workshop](/workshops/static/images/disconnected/connect-prep-ec2.gif)        | 
|:-----------------------------------------------------------------------------:|
| *Connecting to the prep rhel8 ec2 instance*                                   |
</Zoom>


## 2.5 - Downloading required tools

For the purposes of this workshop, rather than downloading mirror content to a USB drive as we would likely do in a real SneakerOps situation, we will instead be saving content to an EBS volume which will be mounted to our prep system on the **Low side** and then subsequently to our bastion system on the **High side**.

Once your prep system has booted let's mount the EBS volume we attached so we can start downloading content. Copy the commands below into your web terminal:

```bash
sudo mkfs -t xfs /dev/nvme1n1
sudo mkdir /mnt/high-side
sudo mount /dev/nvme1n1 /mnt/high-side
sudo chown ec2-user:ec2-user /mnt/high-side
cd /mnt/high-side
```

With our mount in place let's grab the tools we'll need for the bastion server - we'll use some of them on the prep system too. Life's good on the low side; we can download these from the internet and tuck them into our **High side** gift basket at `/mnt/high-side`.

There are four tools we need, copy the commands into your web terminal to download each one:

1. `oc` OpenShift cli

```bash
curl https://mirror.openshift.com/pub/openshift-v4/clients/ocp/stable/openshift-client-linux.tar.gz -L -o oc.tar.gz
tar -xzf oc.tar.gz oc && rm -f oc.tar.gz
sudo cp oc /usr/local/bin/
```

2. `oc-mirror` oc plugin for mirorring release, operator, and helm content

```bash
curl https://mirror.openshift.com/pub/openshift-v4/clients/ocp/stable/oc-mirror.tar.gz -L -o oc-mirror.tar.gz
tar -xzf oc-mirror.tar.gz && rm -f oc-mirror.tar.gz
chmod +x oc-mirror
sudo cp oc-mirror /usr/local/bin/
```

3. `mirror-registry` small-scale Quay registry designed for mirroring

```bash
curl https://mirror.openshift.com/pub/openshift-v4/clients/mirror-registry/latest/mirror-registry.tar.gz -L -o mirror-registry.tar.gz
tar -xzf mirror-registry.tar.gz
rm -f mirror-registry.tar.gz
```

4. `openshift-installer` The OpenShift installer cli

```bash
curl https://mirror.openshift.com/pub/openshift-v4/clients/ocp/stable/openshift-install-linux.tar.gz -L -o openshift-installer.tar.gz
tar -xzf openshift-installer.tar.gz openshift-install
rm -f openshift-installer.tar.gz
```

<Zoom>
|![workshop](/workshops/static/images/disconnected/download-tools.gif)       | 
|:-----------------------------------------------------------------------------:|
| *Downloading required tools with curl*                                        |
</Zoom>


## 2.6 - Mirroring content to disk

The `oc-mirror` plugin supports mirroring content directly from upstream sources to a mirror registry, but since there is an air gap between our **Low side** and **High side**, that's not an option for this lab. Instead, we'll mirror content to a tarball on disk that we can then sneakernet into the bastion server on the **High side**. We'll then mirror from the tarball into the mirror registry from there.

> Note: A pre-requisite for this process is an OpenShift pull secret to authenticate to the Red Hat registries. This has already been created for you to avoid the delay of registering for individual Red Hat accounts during this workhop. You can copy this into your newly created prep system by running `scp -pr -i disco_key .docker ec2-user@$PREP_SYSTEM_IP:` in your web terminal. In a real world scenario this pull secret can be downloaded from https://console.redhat.com/openshift/install/pull-secret.

Let's get started by generating an `ImageSetConfiguration` that describes the parameters of our mirror. Run the command below to generate a boilerplate configuration file, it may take a minute:

```bash
oc mirror init > imageset-config.yaml
```

> Note: You can take a look at the default file by running `cat imageset-config.yaml` in your web terminal. Feel free to pause the workshop tasks for a few minutes and read through the [OpenShift documentation](https://docs.openshift.com/container-platform/4.14/updating/updating_a_cluster/updating_disconnected_cluster/mirroring-image-repository.html#oc-mirror-creating-image-set-config_mirroring-ocp-image-repository) for the different options available within the image set configuration.

To save time and storage, we're going to remove the operator catalogs and mirror only the release images for this workshop. We'll still get a fully functional cluster, but OperatorHub will be empty.

To complete this, remove the operators object from your `imageset-config.yaml` by running the command below in your web terminal:

```
cat << EOF > imageset-config.yaml
kind: ImageSetConfiguration
apiVersion: mirror.openshift.io/v1alpha2
storageConfig:
  local:
    path: ./
mirror:
  platform:
    channels:
    - name: stable-4.14
      type: ocp
  additionalImages:
  - name: registry.redhat.io/ubi8/ubi:latest
  helm: {}
EOF
```

Now we're ready to kick off the mirror! This can take 5-15 minutes so this is a good time to go grab a coffee or take a short break:

```bash
oc mirror --config imageset-config.yaml file:///mnt/high-side
```

Once your content has finished mirroring to disk you've finished exercise 2! 🎉
