Iscsi in a container, communicating via RPC

iscsi-rpc.proto

syntax = "proto3";

package iscsi_rpc;

service Iscsiadm {
    rpc SendArgs(SendArgsRequest) returns (SendArgsReply) {}
    rpc GetInitiatorName(GetInitiatorNameRequest) returns (GetInitiatorNameReply) {}
}

message SendArgsRequest {
    string args = 1;
}

message SendArgsReply {
    string result = 1;
}

message GetInitiatorNameRequest {
}

message GetInitiatorNameReply {
    string name = 1;
}

iscsi.yaml

apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: iscsi
spec:
  updateStrategy:
    type: OnDelete
  selector:
    matchLabels:
      app: iscsi
  template:
    metadata:
      labels:
        app: iscsi
    spec:
      hostNetwork: true
      containers:
      - name: iscsid
        imagePullPolicy: Always
        image: dateraiodev/iscsi:latest
        command: [ "/bin/bash", "-c", "iscsi-recv &2>1 & iscsid-run.sh" ]
        securityContext:
          privileged: true
        volumeMounts:
          - name: devices
            mountPath: /dev
          - name: iscsi-socket
            mountPath: /iscsi-socket
          - name: libmod
            mountPath: /lib/modules
      volumes:
      - name: devices
        hostPath:
          path: /dev
      - name: iscsi-socket
        hostPath:
          path: /var/lib/iscsi-socket
          type: DirectoryOrCreate
      - name: libmod
        hostPath:
          path: /lib/modules

main.go

package main

import (
	"context"
	"flag"
	"fmt"
	"io/ioutil"
	"log"
	"os"
	"time"

	co "common"
	pb "iscsi-rpc"
	"google.golang.org/grpc"
)

const (
	address  = "unix:///var/lib/iscsi-socket/iscsi.sock"
	etcIscsi = "/etc/iscsi"
	iname    = "/etc/iscsi/initiatorname.iscsi"
)

var (
	// Necessary to prevent UDC arguments from showing up
	cli = flag.NewFlagSet(os.Args[0], flag.ExitOnError)

	addr = cli.String("addr", address, "Address to send on")
	args = cli.String("args", "", "Arguments including iscsiadm prefix")
)

func setupInitName(ctxt context.Context, c pb.IscsiadmClient) {
	if _, err := os.Stat(etcIscsi); os.IsNotExist(err) {
		log.Printf("Creating directories: %s\n", addr)
		err = os.MkdirAll(etcIscsi, os.ModePerm)
		if err != nil {
			log.Fatal(err)
		}
		resp, err := c.GetInitiatorName(ctxt, &pb.GetInitiatorNameRequest{})
		if err != nil {
			log.Fatal(err)
		}
		name := fmt.Sprintf("InitiatorName=%s", resp.Name)
		err = ioutil.WriteFile(iname, []byte(name), 0644)
		if err != nil {
		   log.Fatal(err)
		}
	}
}

func main() {
	cli.Parse(os.Args[1:])
	// Set up a connection to the server.
	conn, err := grpc.Dial(*addr, grpc.WithInsecure())
	if err != nil {
		log.Fatalf("did not connect: %v", err)
	}
	defer conn.Close()
	c := pb.NewIscsiadmClient(conn)

	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
	defer cancel()
	setupInitName(ctx, c)
	r, err := c.SendArgs(ctx, &pb.SendArgsRequest{Args: *args})
	if err != nil {
		log.Fatalf("Could not send args: %v", err)
	}
	log.Printf("Iscsiadm Result: %s", r.Result)
}

Forgot to add the dockerfile:

FROM ubuntu:16.04

RUN apt-get update \
 && apt-get -y install open-iscsi \
                       multipath-tools \
 && echo GenerateName=yes > /etc/iscsi/initiatorname.iscsi

COPY assets/multipath.conf /etc/multipath.conf
COPY cmd/dat-csi-plugin/iscsi-recv /usr/local/bin/
COPY deploy/kubernetes/iscsi/iscsid-run.sh /usr/local/bin/

iscsid-recv is just a simple golang file serving the protofile GRPC interface

Multipathd is also enabled in this container image, but it currently blacklists all but Datera devices. Override the multipath.conf file with whatever you want to get non Datera devices working.

iscsid-run.sh:

#!/usr/bin/env bash
set -e
modprobe dm-multipath
service multipath-tools start
/lib/open-iscsi/startup-checks.sh
exec /usr/sbin/iscsid -f