<p>I am using on-prem k8s v1.19 and Istio with 1.8.0.. I got stuck to run them together properly when I inject istio mesh to the <code>hub-dev</code> where our microservices are running. Vault is running <code>dev</code> namespace.</p>
<p>The first issue I had is Vault and Istio sidecar is not running properly somehow and the application can not able to init as below. I tried to use below annotations to init first vault but it did not solve below issue.</p>
<ul>
<li>vault.hashicorp.com/agent-init-first: true</li>
<li>vault.hashicorp.com/agent-inject: true</li>
</ul>
<p>Here are the outputs of pod status and describe</p>
<pre><code>$ kubectl get pods -n hub-dev
    NAME                                     READY   STATUS     RESTARTS   AGE
    oneapihub-mp-dev-59f7685455-5kmft        0/3     Init:0/2   0          19
    
$ kubectl describe pod oneapihub-mp-dev-59f7685455-5kmft -n hub-dev

Init Containers:
  vault-agent-init:
    Container ID:  
    State:          Running
      Started:      Fri, 15 Jan 2021 13:54:30 +0300
    Ready:          False
  istio-validation:
    Container ID:
    Image:         reg-dhc.app.corpintra.net/i3-mirror/docker.io_istio_proxyv2:1.8.0
    State:          Waiting
     Reason:       PodInitializing
    Ready:          False
Containers:
      oneapihub-mp:
        Container ID:
        State:          Waiting
          Reason:       PodInitializing
        Ready:          False
      istio-proxy:
        Container ID:
        State:          Waiting
          Reason:       PodInitializing
        Ready:          False
  istio-proxy:
    Container ID:
    State:          Waiting
      Reason:       PodInitializing
    Ready:          False

    Normal  Pulled     16m   kubelet, xx-kube-node07  Container image &quot;docker.io_vault:1.5.2&quot; already present on machine
    Normal  Created    16m   kubelet, xx-kube-node07  Created container vault-agent-init
    Normal  Started    16m   kubelet, xx-kube-node07  Started container vault-agent-init
</code></pre>
<p>When I tried below annotation, it fixed the above issue, but this time when pod starts to run it can not able to find <code>/vault/secrets</code> path but somehow after that it can be read when I checked the logs of proxy and application and <code>/vault/secrets</code> folder is exist inside pod.</p>
<pre><code> - vault.hashicorp.com/agent-pre-populate: &quot;false&quot;
</code></pre>
<p>Here the logs of app even if folder exists</p>
<pre><code>$ kubectl get pods -n hub-dev
oneapihub-mp-dev-78449b8cf6-qbqhn        3/3     Running   0          9m31s

$ kubectl logs -f oneapihub-mp-dev-78449b8cf6-qbqhn -n hub-dev -c oneapihub-mp

&gt; market-place@1.0.0 start:docker /usr/src/app
&gt; node app.js

{&quot;message&quot;&quot;devMessage&quot;:&quot;SECRET_READ_ERROR&quot;,&quot;data&quot;:&quot;&quot;,&quot;exception&quot;:&quot;ENOENT: no such file or directory, open '/vault/secrets/database'&quot;,&quot;stack&quot;:&quot;Error: ENOENT: no such file or directory, open '/vault/secrets/database'-&gt;

/ $ cd /vault/secrets
/vault/secrets $ ls
database  jenkins
/vault/secrets $
</code></pre>
<p>Here I have some PUT error which might related with Vault itself but I am confuse how then Vault can inject the secrets.</p>
<pre><code> $ kubectl logs -f oneapihub-mp-dev-78449b8cf6-qbqhn -n hub-dev -c vault-agent

2021-01-15T11:21:13.477Z [ERROR] auth.handler: error authenticating: error=&quot;Put &quot;http://vault.dev.svc:8200/v1/auth/kubernetes/login&quot;: dial tcp 10.254.30.115:8200: connect: connection refused&quot; backoff=2.464775515
==&gt; Vault agent started! Log data will stream in below:

==&gt; Vault agent configuration:

                     Cgo: disabled
               Log Level: info
                 Version: Vault v1.5.2
             Version Sha: 685fdfa60d607bca069c09d2d52b6958a7a2febd

2021-01-15T11:21:15.942Z [INFO]  auth.handler: authenticating
2021-01-15T11:21:15.966Z [INFO]  auth.handler: authentication successful, sending token to sinks
2021-01-15T11:21:15.966Z [INFO]  sink.file: token written: path=/home/vault/.vault-token
</code></pre>
<p>And lastly when I checkted the istio-proxy logs I can see that GET or PUT request returns 200.</p>
<pre><code>$ kubectl logs -f oneapihub-mp-dev-78449b8cf6-h8s8j -n hub-dev -c istio-proxy

021-01-15T11:35:04.352221Z  warning envoy filter    mTLS PERMISSIVE mode is used, connection can be either plaintext or TLS, and client cert can be omitted. Please consider to upgrade to mTLS STRICT mode for more secure configuration that only allows TLS connection with client cert. See https://istio.io/docs/tasks/security/mtls-migration/
[2021-01-15T11:35:05.557Z] &quot;PUT /v1/auth/kubernetes/login HTTP/1.1&quot; 200 - &quot;-&quot; 1294 717 8 8 &quot;-&quot; &quot;Go-http-client/1.1&quot; &quot;a082698b-d1f7-4aa5-9db5-01d86d5093ef&quot; &quot;vault.dev.svc:8200&quot; &quot;10.6.24.55:8200&quot; outbound|8200||vault.dev.svc.cluster.local 10.6.19.226:55974 10.254.30.115:8200 10.6.19.226:60478 - default
2021-01-15T11:35:05.724833Z info    Envoy proxy is ready
[2021-010.6.19.226:41888 - default
[2021-01-15T11:35:05.596Z] &quot;GET /v1/secret/data/oneapihub-marketplace/database HTTP/1.1&quot; 200 - &quot;-&quot; 0 400 0 0 &quot;-&quot; &quot;Go-http-client/1.1&quot; &quot;d7d10c1f-c445-44d1-b0e3-bb9ae7bbc2f0&quot; &quot;vault.dev.svc:8200&quot; &quot;10.6.24.55:8200&quot; outbound|8200||vault.dev.svc.cluster.local 10.6.19.226:55974 10.254.30.115:8200 10.6.19.226:41900 - default
[2021-01-15T11:35:05.591Z] &quot;PUT /v1/auth/token/renew-self HTTP/1.1&quot; 200 - &quot;-&quot; 15 717 8 8 &quot;-&quot; &quot;Go-http-client/1.1&quot; &quot;56705e5c-c966-4bc8-8187-7ca5bb2b4abe&quot; &quot;vault.dev.svc:8200&quot; &quot;10.6.24.55:8200&quot; outbound|8200||vault.dev.svc.cluster.local 10.6.19.226:37388 10.254.30.115:8200 10.6.19.226:41890 - default
[2021-01-15T11:35:05.602Z] &quot;GET /v1/secret/data/oneapihub-marketplace/jenkins HTTP/1.1&quot; 200 - &quot;-&quot; 0 284 0 0 &quot;-&quot; &quot;Go-http-client/1.1&quot; &quot;1b6d8601-18df-4f32-8722-162aa785c476&quot; &quot;vault.dev.svc:8200&quot; &quot;10.6.24.55:8200&quot; outbound|8200||vault.dev.svc.cluster.local 10.6.19.226:55974 10.254.30.115:8200 10.6.19.226:41902 - default
</code></pre>

<p>Added below annotations worked for me.</p>
<pre><code>  template:
    metadata:
      annotations:
        traffic.sidecar.istio.io/excludeOutboundPorts: &quot;8200&quot;
        vault.hashicorp.com/agent-init-first: &quot;true&quot;
        vault.hashicorp.com/agent-inject: &quot;true&quot;
</code></pre>
