Questions[cloud-config](server)

I've been to countless sites including this one, trying to figure out how to make LXD run a cloud-config when I launch my LXD container. Some places recommend setting up a profile (didn't work). Others recommend redirecting a YAML file into the lxc command (didn't work), and others recommend using the --config option and passing the file in that way (didn't work). Some places say I have to add #cloud-config to my config, others don't bother. Some even recommend using an XML file. I'm obviously missing some critical piece of information that everyone else just does by default, but I can't figure out what it is.

My updated "simple example" that tries to install tree and tries to touch /run/cloud-config-did-run:

lxc delete -f x

cat << EOF >config.yml
#cloud-config
output: {all: '| tee -a /var/log/my-cloud-init-output.log'}
package_update: true
package_upgrade: true
package_reboot_if_required: true
packages:
  - tree
runcmd:
  - touch /run/cloud-config-did-run
EOF

lxc launch ubuntu: x --config=user.user-data="$(cat config.yml)"
sleep 5
lxc exec x -- bash -c "ls /run"
lxc exec x -- bash -c "tree /etc"

The output DOES get directed to /var/log/my-cloud-init-output.log, so it is getting processed, but nothing other than the output directive runs (the logs don't even mention any other things running, or any errors - just the standard SSH keygen stuff).

Maybe the indentation is wrong? Or the config is in the wrong subtree? Or there's some magic value missing? A version of LXD where this is broken? (I'm running version 4.20). I've been at this for 10 hours so far and no matter what I do, my cloud config is completely ignored (no errors, no logs, no record of anything running, no record that I ever instructed it to do anything - other than the standard ssh keygen stuff that's apparently baked in). Can someone please turn the above into a working example that is guaranteed to run if I just paste it into a shell?

I'm configuring systemd in a cloud-config file for CoreOS. If I understand this correctly, I have two ways of starting a unit at boot:

Alternative 1, use the [Install]-section (as described in digital oceans guides):

- name: initialize_data
  content: |
    [Unit]
    Description=Run a command

    [Service]
    Type=oneshot
    ExecStart=/usr/bin/mkdir /foo

    [Install]
    WantedBy=multi-user.target

Alternative 2, drop the [Install]-section and use command: start:

- name: initialize_data
  command: start
  content: |
    [Unit]
    Description=Run a command

    [Service]
    Type=oneshot
    ExecStart=/usr/bin/mkdir /foo

Is there any drawbacks of starting the unit using command: start? I get that I can't control which unit it will start after, but anything else? Will it honour [Unit]-directives such as Requires= and After=?

I am just getting started with CoreOS, I've been following the step-by-step tutorial about setting up Kubernetes, but I seem to be missing a very basic concept. As I am using Bare Metal, I use the cloud-config-url parameter pointing to an NGINX webserver giving back some very basic cloud-config file which replaces the ip of the host (as given by dhcp). Something like this:

#cloud-config
coreos:
  etcd2:
    discovery: "https://discovery.etcd.io/2ab74sd3a59583012056187ee8b74e9a"
    advertise-client-urls: "http://$public_ipv4:2379"
    initial-advertise-peer-urls: "http://$public_ipv4:2380"
    listen-client-urls: "http://0.0.0.0:2379,http://0.0.0.0:4001"
    listen-peer-urls: "http://$public_ipv4:2380,http://$public_ipv4:7001"
  units:
    - name: etcd2.service
      command: start
    - name: fleet.service
      command: start
ssh_authorized_keys:
....

This is fine. It works.

But what if I want to run a service that does not include the etcd2configuration? or add a service to a specific subset of servers? How do you guys handle that case?

Are there more parameters or headers passed by the kernel to the cloud-config-url? how could I use that in NGINX?

Thanks for your feedback

How can a cloud-config script copy a file to a server? write_files requires the file content in the script. How can I specify an external file that contains the content?

I am defining a one-shot service in my CoreOS cloud-config, but it is failing due to not being able to download files from Google Cloud Storage (via wget):

Apr 13 11:09:56 staging-node-ys9y.c.experimentalberlin.internal sh[1132]: Connecting to storage.googleapis.com|74.125.133.128|:443... failed: Connection timed out.

How should I ensure that the service be able to download files from the Internet?

My cloud-config

#cloud-config
coreos:
  units:
    - name: bootstrap.service
      command: start
      content: |
        [Unit]
        Description=Bootstrap instance
        After=network-online.target
        Requires=network-online.target

        [Service]
        Type=oneshot
        RemainAfterExit=true
        ExecStart=/usr/bin/mkdir -p /tmp/kubernetes-staging
        ExecStart=cd /tmp/kubernetes-staging
        ExecStart=/bin/sh -c "cd /tmp/kubernetes-staging && wget https://storage.googleapis.com/experimentalberlin/staging.tar.gz && tar xf staging.tar.gz"
        ExecStart=/tmp/kubernetes-staging/worker/bootstrap.sh

        [Install]
        WantedBy=local.target