kubeadm HA guide: fix indentation and use EOF instead of EOL (#7249)

* Use EOF instead of EOL in HA guide

This is for consistency with the rest of the docs.

* Change indentation from 4 to 3 spaces

The number of spaces in indentation is expected to be divisible by 3.
By having 4 spaces, an extra space was added to the beginning of all
shell code sections, causing issues for heredoc interpretation on
copy/paste.

docs/setup/independent/high-availability.md

@@ -67,7 +67,7 @@ For **Option 2**: you can skip to the next step. Any reference to `etcd0`, `etcd
    cd /etc/kubernetes/pki/etcd
    ```
    ```shell
-    cat >ca-config.json <<EOL
+   cat >ca-config.json <<EOF
    {
        "signing": {
            "default": {
@@ -103,10 +103,10 @@ For **Option 2**: you can skip to the next step. Any reference to `etcd0`, `etcd
            }
        }
    }
-    EOL
+   EOF
    ```
    ```shell
-    cat >ca-csr.json <<EOL
+   cat >ca-csr.json <<EOF
    {
        "CN": "etcd",
        "key": {
@@ -114,7 +114,7 @@ For **Option 2**: you can skip to the next step. Any reference to `etcd0`, `etcd
            "size": 2048
        }
    }
-    EOL
+   EOF
    ```
 
    Ensure that the `names` section in `ca-csr.json` matches your own company or personal address, or that you use a suitable default.
@@ -132,7 +132,7 @@ For **Option 2**: you can skip to the next step. Any reference to `etcd0`, `etcd
    While on `etcd0`, run the following:
 
    ```shell
-    cat >client.json <<EOL
+   cat >client.json <<EOF
    {
        "CN": "client",
        "key": {
@@ -140,7 +140,7 @@ For **Option 2**: you can skip to the next step. Any reference to `etcd0`, `etcd
            "size": 256
        }
    }
-    EOL
+   EOF
    ```
    ```shell
    cfssl gencert -ca=ca.pem -ca-key=ca-key.pem -config=ca-config.json -profile=client client.json | cfssljson -bare client
@@ -243,7 +243,7 @@ Please select one of the tabs to see installation instructions for the respectiv
 1. Now copy the systemd unit file like so:
 
    ```shell
-    cat >/etc/systemd/system/etcd.service <<EOL
+   cat >/etc/systemd/system/etcd.service <<EOF
    [Unit]
    Description=etcd
    Documentation=https://github.com/coreos/etcd
@@ -278,7 +278,7 @@ Please select one of the tabs to see installation instructions for the respectiv
 
    [Install]
    WantedBy=multi-user.target
-    EOL
+   EOF
    ```
 
    Make sure you replace `<etcd0-ip-address>`, `<etcd1-ip-address>` and `<etcd2-ip-address>` with the appropriate IPv4 addresses.
@@ -304,7 +304,7 @@ Please select one of the tabs to see installation instructions for the respectiv
 1. The first step is to run the following to generate the manifest file:
 
    ```shell
-    cat >/etc/kubernetes/manifests/etcd.yaml <<EOL
+   cat >/etc/kubernetes/manifests/etcd.yaml <<EOF
    apiVersion: v1
    kind: Pod
    metadata:
@@ -369,7 +369,7 @@ Please select one of the tabs to see installation instructions for the respectiv
    - hostPath:
        path: /etc/kubernetes/pki/etcd
        name: certs
-    EOL
+   EOF
    ```
 
    Make sure you replace:
@@ -415,7 +415,7 @@ Only follow this step if your etcd is hosted on dedicated nodes (**Option 1**).
 1. In order for kubeadm to run, you first need to write a configuration file:
 
    ```shell
-    cat >config.yaml <<EOL
+   cat >config.yaml <<EOF
    apiVersion: kubeadm.k8s.io/v1alpha1
    kind: MasterConfiguration
    api:
@@ -434,7 +434,7 @@ Only follow this step if your etcd is hosted on dedicated nodes (**Option 1**).
    - <load-balancer-ip>
    apiServerExtraArgs:
      apiserver-count: 3
-    EOL
+   EOF
    ```
 
    Ensure that the following placeholders are replaced: