Done according to this article.

I installed Kubernetes. Then installed etcd cluster that works via HTTPS and listens to the localhost interface only (reachable from inside any Docker container). Now I need persistent volume to install DB cluster. Chose Portworx. It generated daemonset YAML-config. Here is the description of installed daemonset:

# kubectl describe daemonset portworx --namespace=kube-system

Name:           portworx
Selector:       name=portworx
Node-Selector:  <none>
Labels:         name=portworx
Annotations:    kubectl.kubernetes.io/last-applied-configuration={"apiVersion":"extensions/v1beta1","kind":"DaemonSet","metadata":{"annotations":{"portworx.com/install-source":"http://install.portworx.com/?c=bp_clust...
                portworx.com/install-source=http://install.portworx.com/?c=bp_cluster&k=etcd:https://127.0.0.1:2379&kbver=1.11.0&s=/dev/xvda1&d=ens3&m=ens3&stork=false&ca=/etc/kubernetes/pki/etcd/ca.crt%%20&cert=/etc...
Desired Number of Nodes Scheduled: 2
Current Number of Nodes Scheduled: 2
Number of Nodes Scheduled with Up-to-date Pods: 2
Number of Nodes Scheduled with Available Pods: 0
Number of Nodes Misscheduled: 0
Pods Status:  2 Running / 0 Waiting / 0 Succeeded / 0 Failed
Pod Template:
  Labels:           name=portworx
  Service Account:  px-account
  Containers:
   portworx:
    Image:      portworx/oci-monitor:1.3.4
    Port:       <none>
    Host Port:  <none>
    Args:
      -k
      etcd:https://127.0.0.1:2379
      -c
      bp_cluster
      -d
      ens3
      -m
      ens3
      -s
      /dev/xvda1
      -ca
      /etc/kubernetes/pki/etcd/ca.crt 
      -cert
      /etc/kubernetes/pki/etcd/server.crt
      -key
      /etc/kubernetes/pki/etcd/server.key
      -x
      kubernetes
    Liveness:   http-get http://127.0.0.1:9001/status delay=840s timeout=1s period=30s #success=1 #failure=3
    Readiness:  http-get http://127.0.0.1:9015/health delay=0s timeout=1s period=10s #success=1 #failure=3
    Environment:
      PX_TEMPLATE_VERSION:  v3
    Mounts:
      /etc/pwx from etcpwx (rw)
      /etc/systemd/system from sysdmount (rw)
      /host_proc/1/ns from proc1nsmount (rw)
      /opt/pwx from optpwx (rw)
      /var/run/dbus from dbusmount (rw)
      /var/run/docker.sock from dockersock (rw)
  Volumes:
   dockersock:
    Type:          HostPath (bare host directory volume)
    Path:          /var/run/docker.sock
    HostPathType:  
   etcpwx:
    Type:          HostPath (bare host directory volume)
    Path:          /etc/pwx
    HostPathType:  
   optpwx:
    Type:          HostPath (bare host directory volume)
    Path:          /opt/pwx
    HostPathType:  
   proc1nsmount:
    Type:          HostPath (bare host directory volume)
    Path:          /proc/1/ns
    HostPathType:  
   sysdmount:
    Type:          HostPath (bare host directory volume)
    Path:          /etc/systemd/system
    HostPathType:  
   dbusmount:
    Type:          HostPath (bare host directory volume)
    Path:          /var/run/dbus
    HostPathType:  
Events:
  Type    Reason            Age   From                  Message
  ----    ------            ----  ----                  -------
  Normal  SuccessfulCreate  22m   daemonset-controller  Created pod: portworx-67w7m
  Normal  SuccessfulCreate  22m   daemonset-controller  Created pod: portworx-mxtr8

But in the log of portworx I see that it is trying to connect to etcd via plain HTTP and obviously get error because cannot interpreter the response wrapped to SSL:

# kubectl logs -f pod/portworx-67w7m --namespace=kube-system

<some logs are erased du to lack of relevance>

Jul 02 13:19:25 ip-172-31-18-91 px-runc[25417]: time="2018-07-02T13:19:25Z" level=error msg="Could not load config file /etc/pwx/config.json due to: Error in obtaining etcd version: Get http://127.0.0.1:2379/version: net/http: HTTP/1.x transport connection broken: malformed HTTP response \"\\x15\\x03\\x01\\x00\\x02\\x02\".  Please visit http://docs.portworx.com for more information."
Jul 02 13:19:25 ip-172-31-18-91 px-runc[25417]: PXPROCS: px daemon exited with code: 1
Jul 02 13:19:25 ip-172-31-18-91 px-runc[25417]: 2107
Jul 02 13:19:25 ip-172-31-18-91 px-runc[25417]: 2018-07-02 13:19:25,474 INFO exited: pxdaemon (exit status 1; not expected)

What I am doing wrong?