From 809e9cd73cb06ffc2230f3e534e799b6459f0b31 Mon Sep 17 00:00:00 2001
From: Xan Manning <xan.manning@gmail.com>
Date: Sat, 25 Jul 2020 14:03:53 +0100
Subject: [PATCH] Releasable feature for hardlinks

---
 README.md                     | 43 +++++++++++++++++++++++++++++++++++
 defaults/main.yml             |  3 +++
 molecule/default/playbook.yml |  2 ++
 tasks/build/install-k3s.yml   | 12 +++++-----
 4 files changed, 54 insertions(+), 6 deletions(-)

diff --git a/README.md b/README.md
index e9fc42d..4b4534d 100644
--- a/README.md
+++ b/README.md
@@ -50,6 +50,7 @@ consistency.
 | `k3s_build_cluster`                      | When multiple `play_hosts` are available, attempt to cluster. Read notes below.     | `true`                                  |
 | `k3s_github_url`                         | Set the GitHub URL to install k3s from.                                             | https://github.com/rancher/k3s          |
 | `k3s_install_dir`                        | Installation directory for k3s.                                                     | `/usr/local/bin`                        |
+| `k3s_install_hard_links`                 | Install using hard links rather than symbolic links.                                | `false`                                 |
 | `k3s_server_manifests_dir`               | Path for place the `k3s_server_manifests_templates`.                                | `/var/lib/rancher/k3s/server/manifests` |
 | `k3s_server_manifests_templates`         | A list of Auto-Deploying Manifests Templates.                                       | []                                      |
 | `k3s_use_experimental`                   | Allow the use of experimental features in k3s.                                      | `false`                                 |
@@ -117,6 +118,48 @@ k3s_release_version: v1.18          # latest v1.18 release
 k3s_release_version: v1.17-testing  # latest v1.17 testing release
 ```
 
+#### Important node about `k3s_install_hard_links`
+
+If you are using the [system-upgrade-controller](https://github.com/rancher/system-upgrade-controller)
+you will need to use hard links rather than symbolic links as the controller
+will not be able to follow symbolic links. This option has been added however
+is not enabled by default to avoid breaking existing installations.
+
+To enable the use of hard links, ensure `k3s_install_hard_links` is set
+to `true`.
+
+```yaml
+k3s_install_hard_links: true
+```
+
+The result of this can be seen by running the following in `k3s_install_dir`:
+
+`ls -larthi | grep -E 'k3s|ctr|ctl' | grep -vE ".sh$" | sort`
+
+Symbolic Links:
+
+```text
+[root@node1 bin]# ls -larthi | grep -E 'k3s|ctr|ctl' | grep -vE ".sh$" | sort
+3277823 -rwxr-xr-x 1 root root  52M Jul 25 12:50 k3s-v1.18.4+k3s1
+3279565 lrwxrwxrwx 1 root root   31 Jul 25 12:52 k3s -> /usr/local/bin/k3s-v1.18.6+k3s1
+3279644 -rwxr-xr-x 1 root root  51M Jul 25 12:52 k3s-v1.18.6+k3s1
+3280079 lrwxrwxrwx 1 root root   31 Jul 25 12:52 ctr -> /usr/local/bin/k3s-v1.18.6+k3s1
+3280080 lrwxrwxrwx 1 root root   31 Jul 25 12:52 crictl -> /usr/local/bin/k3s-v1.18.6+k3s1
+3280081 lrwxrwxrwx 1 root root   31 Jul 25 12:52 kubectl -> /usr/local/bin/k3s-v1.18.6+k3s1
+```
+
+Hard Links:
+
+```text
+[root@node1 bin]# ls -larthi | grep -E 'k3s|ctr|ctl' | grep -vE ".sh$" | sort
+3277823 -rwxr-xr-x 1 root root  52M Jul 25 12:50 k3s-v1.18.4+k3s1
+3279644 -rwxr-xr-x 5 root root  51M Jul 25 12:52 crictl
+3279644 -rwxr-xr-x 5 root root  51M Jul 25 12:52 ctr
+3279644 -rwxr-xr-x 5 root root  51M Jul 25 12:52 k3s
+3279644 -rwxr-xr-x 5 root root  51M Jul 25 12:52 k3s-v1.18.6+k3s1
+3279644 -rwxr-xr-x 5 root root  51M Jul 25 12:52 kubectl
+```
+
 #### Important note about `k3s_build_cluster`
 
 If you set `k3s_build_cluster` to `false`, this role will install each play
diff --git a/defaults/main.yml b/defaults/main.yml
index d55e44e..05a106d 100644
--- a/defaults/main.yml
+++ b/defaults/main.yml
@@ -19,6 +19,9 @@ k3s_github_url: https://github.com/rancher/k3s
 # Installation directory for k3s
 k3s_install_dir: /usr/local/bin
 
+# Install using hard links rather than symbolic links
+k3s_install_hard_links: false
+
 # Path for additional Kubernetes Manifests
 # https://rancher.com/docs/k3s/latest/en/advanced/#auto-deploying-manifests
 k3s_server_manifests_dir: /var/lib/rancher/k3s/server/manifests
diff --git a/molecule/default/playbook.yml b/molecule/default/playbook.yml
index 394481e..c3454bd 100644
--- a/molecule/default/playbook.yml
+++ b/molecule/default/playbook.yml
@@ -4,5 +4,7 @@
   become: true
   vars:
     molecule_is_test: true
+    k3s_release_version: v1.18.6+k3s1
+    k3s_install_hard_links: true
   roles:
     - role: xanmanning.k3s
diff --git a/tasks/build/install-k3s.yml b/tasks/build/install-k3s.yml
index c4f75a8..7e5c945 100644
--- a/tasks/build/install-k3s.yml
+++ b/tasks/build/install-k3s.yml
@@ -1,11 +1,11 @@
 ---
 
-- name: Ensure k3s is hard linked into the installation destination on the contol plane
+- name: Ensure k3s is linked into the installation destination on the contol plane
   file:
     src: "{{ k3s_install_dir }}/k3s-{{ k3s_release_version }}"
     dest: "{{ k3s_install_dir }}/k3s"
-    state: hard
-    force: true
+    state: "{{ 'hard' if k3s_install_hard_links else 'link' }}"
+    force: "{{ k3s_install_hard_links }}"
   when: (k3s_control_node and k3s_controller_count | length == 1)
         or (k3s_primary_control_node and k3s_controller_count | length > 1)
   notify:
@@ -45,12 +45,12 @@
     mode: 0700
   become: "{{ k3s_become_for_usr_local_bin | ternary(true, false, k3s_become_for_all) }}"
 
-- name: Ensure k3s is hard linked into the installation destinations across all nodes
+- name: Ensure k3s is linked into the installation destinations across all nodes
   file:
     src: "{{ k3s_install_dir }}/k3s-{{ k3s_release_version }}"
     dest: "{{ k3s_install_dir }}/{{ item }}"
-    state: hard
-    force: true
+    state: "{{ 'hard' if k3s_install_hard_links else 'link' }}"
+    force: "{{ k3s_install_hard_links }}"
   notify:
     - restart k3s
   loop: