I'm attempting to connect to a CloudSQL instance via a cloudsql-proxy container on my Kubernetes deployment. I have the cloudsql credentials mounted and the value of GOOGLE_APPLICATION_CREDENTIALS set.

However, I'm still receiving the following error in my logs:

2018/10/08 20:07:28 Failed to connect to database: Post https://www.googleapis.com/sql/v1beta4/projects/[projectID]/instances/[appName]/createEphemeral?alt=json&prettyPrint=false: oauth2: cannot fetch token: Post https://oauth2.googleapis.com/token: x509: certificate signed by unknown authority

My connection string looks like this:

[dbUser]:[dbPassword]@cloudsql([instanceName])/[dbName]]?charset=utf8&parseTime=True&loc=Local

And the proxy dialer is shadow-imported as:

_ github.com/GoogleCloudPlatform/cloudsql-proxy/proxy/dialers/mysql

Anyone have an idea what might be missing?

EDIT:

Deployment Spec looks something like this (JSON formatted):

{
  "replicas": 1,
  "selector": {
    ...
  },
  "template": {
    ...
    "spec": {
      "containers": [
        {
          "image": "[app-docker-imager]",
          "name": "...",
          "env": [
            ...
            {
              "name": "MYSQL_PASSWORD",
              ...
            },
            {
              "name": "MYSQL_USER",
              ...
            },
            {
              "name": "GOOGLE_APPLICATION_CREDENTIALS",
              "value": "..."
            }
          ],

          "ports": [
            {
              "containerPort": 8080,
              "protocol": "TCP"
            }
          ],
          "volumeMounts": [
            {
              "mountPath": "/secrets/cloudsql",
              "name": "[secrets-mount-name]",
              "readOnly": true
            }
          ]
        },
        {
          "command": [
            "/cloud_sql_proxy",
            "-instances=...",
            "-credential_file=..."
          ],
          "image": "gcr.io/cloudsql-docker/gce-proxy:1.11",
          "name": "...",
          "ports": [
            {
              "containerPort": 3306,
              "protocol": "TCP"
            }
          ],
          "volumeMounts": [
            {
              "mountPath": "/secrets/cloudsql",
              "name": "[secrets-mount-name]",
              "readOnly": true
            }
          ]
        }
      ],
      "volumes": [
        {
          "name": "[secrets-mount-name]",
          "secret": {
            "defaultMode": 420,
            "secretName": "[secrets-mount-name]"
          }
        }
      ]
    }
  }
}