General revamp of docs to point to newer ubuntu LTS

docs/install/amazon.rst

@@ -58,15 +58,15 @@ Let's create the server on which we can run JupyterHub.
 #. On the page **Step 1: Choose an Amazon Machine Image (AMI)** you are going
    to pick the base image your remote server will have. The view will
    default to the 'Quick-start' tab selected and just a few down the page, select
-   **Ubuntu Server 18.04 LTS (HVM), SSD Volume Type - ami-XXXXXXXXXXXXXXXXX**,
+   **Ubuntu Server 22.04 LTS (HVM), SSD Volume Type - ami-XXXXXXXXXXXXXXXXX**,
    leaving `64-bit (x86)` toggled.
 
    .. image:: ../images/providers/amazon/select_ubuntu_18.png
-      :alt: Click Ubuntu server 18.04
+      :alt: Click Ubuntu server 22.04
 
    The `ami` alpha-numeric at the end references the specific Amazon machine
    image, ignore this as Amazon updates them routinely. The
-   **Ubuntu Server 18.04 LTS (HVM)** is the important part.
+   **Ubuntu Server 22.04 LTS (HVM)** is the important part.
 
 
 #. After selecting the AMI, you'll be at **Step 2: Choose an Instance Type**.

docs/install/azure.rst

@@ -52,7 +52,7 @@ A new screen with all the options for Virtual Machines in Azure will displayed.
         :alt: Create VM from the marketplace
 
 #. **Choose an Ubuntu server for your VM**: 
-    * Click `Ubuntu Server 18.04 LTS.`
+    * Click `Ubuntu Server 22.04 LTS.`
     * Make sure `Resource Manager` is selected in the next screen and click **Create**
 
     .. image:: ../images/providers/azure/ubuntu-vm.png
@@ -70,7 +70,7 @@ A new screen with all the options for Virtual Machines in Azure will displayed.
     * **Name**. Use a descriptive name for your virtual machine (note that you cannot use spaces or special characters).
     * **Region**. Choose a location near where you expect your users to be located.
     * **Availability options**. Choose "No infrastructure redundancy required".
-    * **Image**. Make sure "Ubuntu Server 18.04 LTS" is selected (from the previous step).
+    * **Image**. Make sure "Ubuntu Server 22.04 LTS" is selected (from the previous step).
     * **Authentication type**. Change authentication type to "password".
     * **Username**. Choose a memorable username, this will be your "root" user, and you'll need it later on.
     * **Password**. Type in a password, this will be used later for admin access so make sure it is something memorable.

docs/install/custom-server.rst

@@ -31,7 +31,7 @@ Pre-requisites
 ==============
 
 #. Some familiarity with the command line.
-#. A server running Ubuntu 18.04+ where you have root access.
+#. A server running Ubuntu 18.04+ where you have root access (Ubuntu 22.04 LTS recommended).
 #. At least **1GB** of RAM on your server.
 #. Ability to ``ssh`` into the server & run commands from the prompt.
 #. An **IP address** where the server can be reached from the browsers of your target audience.

docs/install/digitalocean.rst

@@ -34,10 +34,10 @@ Let's create the server on which we can run JupyterHub.
    This takes you to a page titled **Create Droplets** that lets you configure
    your server.
 
-#. Under **Choose an image**, select **18.04 x64** under **Ubuntu**.
+#. Under **Choose an image**, select **22.04 x64** under **Ubuntu**.
 
    .. image:: ../images/providers/digitalocean/select-image.png
-      :alt: Select 18.04 x64 image under Ubuntu
+      :alt: Select 22.04 x64 image under Ubuntu
 
 #. Under **Choose a size**, select the size of the server you want. The default
    (4GB RAM, 2CPUs, 20 USD / month) is not a bad start. You can resize your server

docs/install/google.rst

@@ -94,10 +94,10 @@ Let's create the server on which we can run JupyterHub.
 
    This should open a **Boot disk** popup.
 
-#. Select **Ubuntu 18.04 LTS** from the list of operating system images.
+#. Select **Ubuntu 22.04 LTS** from the list of operating system images.
 
    .. image:: ../images/providers/google/boot-disk-ubuntu.png
-      :alt: Selecting Ubuntu 18.04 for OS
+      :alt: Selecting Ubuntu 22.04 for OS
 
 #. You can also change the **type** and **size** of your disk at the bottom
    of this popup.

docs/install/index.rst

@@ -5,7 +5,7 @@ Installing
 ==========
 
 The Littlest JupyterHub (TLJH) can run on any server that is running at least
-**Ubuntu 18.04**. Earlier versions of Ubuntu are not supported.
+**Ubuntu 18.04 (22.04 LTS recommended)**. Earlier versions of Ubuntu are not supported.
 We have a bunch of tutorials to get you started.
 
 Tutorials to create a new server from scratch on a cloud provider & run TLJH

docs/install/jetstream.rst

@@ -33,11 +33,11 @@ Let's create the server on which we can run JupyterHub.
    This takes you to a page with a list of base images you can choose for your
    server.
 
-#. Under **Image Search**, search for **Ubuntu 18.04**, and select the
-   **Ubuntu 18.04 Devel and Docker** image.
+#. Under **Image Search**, search for **Ubuntu 22.04**, and select the
+   **Ubuntu 22.04 Devel and Docker** image.
 
    .. image:: ../images/providers/jetstream/select-image.png
-      :alt: Select Ubuntu 18.04 x64 image from image list
+      :alt: Select Ubuntu 22.04 x64 image from image list
 
 #. Once selected, you will see more information about this image. Click the
    **Launch** button on the top right.

docs/install/ovh.rst

@@ -52,10 +52,10 @@ Let's create the server on which we can run JupyterHub.
       
 #. **Select a region**.
 
-#. Select **Ubuntu 18.04** as the image:
+#. Select **Ubuntu 22.04** as the image:
 
    .. image:: ../images/providers/ovh/distribution.png
-      :alt: Select Ubuntu 18.04 as the image
+      :alt: Select Ubuntu 22.04 as the image
 
 #. OVH requires setting an SSH key to be able to connect to the instance.
    You can create a new SSH by following