diff --git a/src/broker/broker.c b/src/broker/broker.c
index 220f5fe44fe8..a0eaa1508532 100644
--- a/src/broker/broker.c
+++ b/src/broker/broker.c
@@ -187,13 +187,15 @@ static int create_persistdir (attr_t *attrs, uint32_t rank);
 static int create_rundir (attr_t *attrs);
 static int create_dummyattrs (flux_t *h, uint32_t rank, uint32_t size);
 
-static char *calc_endpoint (broker_ctx_t *ctx, const char *endpoint);
+static char *calc_endpoint (attr_t *attrs, const char *endpoint);
 
-static int boot_pmi (broker_ctx_t *ctx, double *elapsed_sec);
+static int boot_pmi (overlay_t *overlay, attr_t *attrs, int tbon_k,
+                     uint32_t *rank_out, uint32_t *size_out,
+                     double *elapsed_sec);
 
 static int attr_get_overlay (const char *name, const char **val, void *arg);
 
-static void init_attrs (broker_ctx_t *ctx);
+static void init_attrs (attr_t *attrs, pid_t pid);
 
 static const struct flux_handle_ops broker_handle_ops;
 
@@ -228,6 +230,79 @@ static void usage (void)
     exit (1);
 }
 
+void parse_command_line_arguments(int argc, char *argv[],
+                                  broker_ctx_t *ctx, int *sec_typemask)
+{
+    int c;
+    int e;
+    char *endptr;
+
+    while ((c = getopt_long (argc, argv, OPTIONS, longopts, NULL)) != -1) {
+        switch (c) {
+        case 's':   /* --security=MODE */
+            if (!strcmp (optarg, "none")) {
+                *sec_typemask = 0;
+            } else if (!strcmp (optarg, "plain")) {
+                *sec_typemask |= FLUX_SEC_TYPE_PLAIN;
+                *sec_typemask &= ~FLUX_SEC_TYPE_CURVE;
+            } else if (!strcmp (optarg, "curve")) {
+                *sec_typemask |= FLUX_SEC_TYPE_CURVE;
+                *sec_typemask &= ~FLUX_SEC_TYPE_PLAIN;
+            } else {
+                log_msg_exit ("--security arg must be none|plain|curve");
+            }
+            break;
+        case 'v':   /* --verbose */
+            ctx->verbose = true;
+            break;
+        case 'q':   /* --quiet */
+            ctx->quiet = true;
+            break;
+        case 'X':   /* --module-path PATH */
+            if (attr_set (ctx->attrs, "conf.module_path", optarg, true) < 0)
+                log_err_exit ("setting conf.module_path attribute");
+            break;
+        case 'k':   /* --k-ary k */
+            errno = 0;
+            ctx->tbon.k = strtoul (optarg, &endptr, 10);
+            if (errno || *endptr != '\0')
+                log_err_exit ("k-ary '%s'", optarg);
+            if (ctx->tbon.k < 1)
+                usage ();
+            break;
+        case 'H':   /* --heartrate SECS */
+            if (heartbeat_set_ratestr (ctx->heartbeat, optarg) < 0)
+                log_err_exit ("heartrate `%s'", optarg);
+            break;
+        case 'g':   /* --shutdown-grace SECS */
+            errno = 0;
+            ctx->shutdown_grace = strtod (optarg, &endptr);
+            if (errno || *endptr != '\0')
+                log_err_exit ("shutdown-grace '%s'", optarg);
+            if (ctx->shutdown_grace < 0)
+                usage ();
+            break;
+        case 'S': { /* --setattr ATTR=VAL */
+            char *val, *attr = xstrdup (optarg);
+            if ((val = strchr (attr, '=')))
+                *val++ = '\0';
+            if (attr_add (ctx->attrs, attr, val, 0) < 0)
+                if (attr_set (ctx->attrs, attr, val, true) < 0)
+                    log_err_exit ("setattr %s=%s", attr, val);
+            free (attr);
+            break;
+        }
+        default:
+            usage ();
+        }
+    }
+    if (optind < argc) {
+        if ((e = argz_create (argv + optind, &ctx->init_shell_cmd,
+                              &ctx->init_shell_cmd_len)) != 0)
+            log_errn_exit (e, "argz_create");
+    }
+}
+
 static int setup_profiling (const char *program, int rank)
 {
 #if HAVE_CALIPER
@@ -246,12 +321,9 @@ static int setup_profiling (const char *program, int rank)
 
 int main (int argc, char *argv[])
 {
-    int c;
     broker_ctx_t ctx;
     zlist_t *sigwatchers;
     int sec_typemask = FLUX_SEC_TYPE_CURVE | FLUX_SEC_TYPE_MUNGE;
-    int e;
-    char *endptr;
     sigset_t old_sigmask;
     struct sigaction old_sigact_int;
     struct sigaction old_sigact_term;
@@ -281,76 +353,13 @@ int main (int argc, char *argv[])
 
     ctx.pid = getpid();
 
-    init_attrs (&ctx);
+    init_attrs (ctx.attrs, ctx.pid);
 
     if (!(ctx.sm = subprocess_manager_create ()))
         oom ();
     subprocess_manager_set (ctx.sm, SM_WAIT_FLAGS, WNOHANG);
 
-    while ((c = getopt_long (argc, argv, OPTIONS, longopts, NULL)) != -1) {
-        switch (c) {
-            case 's':   /* --security=MODE */
-                if (!strcmp (optarg, "none")) {
-                    sec_typemask = 0;
-                } else if (!strcmp (optarg, "plain")) {
-                    sec_typemask |= FLUX_SEC_TYPE_PLAIN;
-                    sec_typemask &= ~FLUX_SEC_TYPE_CURVE;
-                } else if (!strcmp (optarg, "curve")) {
-                    sec_typemask |= FLUX_SEC_TYPE_CURVE;
-                    sec_typemask &= ~FLUX_SEC_TYPE_PLAIN;
-                } else {
-                    log_msg_exit ("--security arg must be none|plain|curve");
-                }
-                break;
-            case 'v':   /* --verbose */
-                ctx.verbose = true;
-                break;
-            case 'q':   /* --quiet */
-                ctx.quiet = true;
-                break;
-            case 'X':   /* --module-path PATH */
-                if (attr_set (ctx.attrs, "conf.module_path", optarg, true) < 0)
-                    log_err_exit ("setting conf.module_path attribute");
-                break;
-            case 'k':   /* --k-ary k */
-                errno = 0;
-                ctx.tbon.k = strtoul (optarg, &endptr, 10);
-                if (errno || *endptr != '\0')
-                    log_err_exit ("k-ary '%s'", optarg);
-                if (ctx.tbon.k < 1)
-                    usage ();
-                break;
-            case 'H':   /* --heartrate SECS */
-                if (heartbeat_set_ratestr (ctx.heartbeat, optarg) < 0)
-                    log_err_exit ("heartrate `%s'", optarg);
-                break;
-            case 'g':   /* --shutdown-grace SECS */
-                errno = 0;
-                ctx.shutdown_grace = strtod (optarg, &endptr);
-                if (errno || *endptr != '\0')
-                    log_err_exit ("shutdown-grace '%s'", optarg);
-                if (ctx.shutdown_grace < 0)
-                    usage ();
-                break;
-            case 'S': { /* --setattr ATTR=VAL */
-                char *val, *attr = xstrdup (optarg);
-                if ((val = strchr (attr, '=')))
-                    *val++ = '\0';
-                if (attr_add (ctx.attrs, attr, val, 0) < 0)
-                    if (attr_set (ctx.attrs, attr, val, true) < 0)
-                        log_err_exit ("setattr %s=%s", attr, val);
-                free (attr);
-                break;
-            }
-            default:
-                usage ();
-        }
-    }
-    if (optind < argc) {
-        if ((e = argz_create (argv + optind, &ctx.init_shell_cmd,
-                                             &ctx.init_shell_cmd_len)) != 0)
-            log_errn_exit (e, "argz_create");
-    }
+    parse_command_line_arguments(argc, argv, &ctx, &sec_typemask);
 
     /* Record the instance owner: the effective uid of the broker.
      * Set default rolemask for messages sent with flux_send()
@@ -430,7 +439,8 @@ int main (int argc, char *argv[])
     /* Boot with PMI.
      */
     double pmi_elapsed_sec;
-    if (boot_pmi (&ctx, &pmi_elapsed_sec) < 0)
+    if (boot_pmi (ctx.overlay, ctx.attrs, ctx.tbon.k,
+                  &ctx.rank, &ctx.size, &pmi_elapsed_sec) < 0)
         log_msg_exit ("bootstrap failed");
 
     assert (ctx.rank != FLUX_NODEID_ANY);
@@ -592,13 +602,6 @@ int main (int argc, char *argv[])
     if (overlay_connect (ctx.overlay) < 0)
         log_err_exit ("overlay_connect");
 
-    {
-        const char *rundir;
-        if (attr_get (ctx.attrs, "broker.rundir", &rundir, NULL) < 0) {
-            log_msg_exit ("broker.rundir attribute is not set");
-        }
-    }
-
     shutdown_set_handle (ctx.shutdown, ctx.h);
     shutdown_set_callback (ctx.shutdown, shutdown_cb, &ctx);
 
@@ -759,31 +762,31 @@ static void init_attrs_from_environment (attr_t *attrs)
     }
 }
 
-static void init_attrs_overlay (broker_ctx_t *ctx)
+static void init_attrs_overlay (attr_t *attrs)
 {
-    char *tbonendpoint = "tbon.endpoint";
-    char *mcastendpoint = "mcast.endpoint";
+    const char *tbonendpoint = "tbon.endpoint";
+    const char *mcastendpoint = "mcast.endpoint";
 
-    if (attr_add (ctx->attrs,
+    if (attr_add (attrs,
                   tbonendpoint,
                   "tcp://%h:*",
                   0) < 0)
         log_err_exit ("attr_add %s", tbonendpoint);
 
-    if (attr_add (ctx->attrs,
+    if (attr_add (attrs,
                   mcastendpoint,
                   "tbon",
                   0) < 0)
         log_err_exit ("attr_add %s", mcastendpoint);
 }
 
-static void init_attrs_broker_pid (broker_ctx_t *ctx)
+static void init_attrs_broker_pid (attr_t *attrs, pid_t pid)
 {
     char *attrname = "broker.pid";
     char *pidval;
 
-    pidval = xasprintf ("%u", ctx->pid);
-    if (attr_add (ctx->attrs,
+    pidval = xasprintf ("%u", pid);
+    if (attr_add (attrs,
                   attrname,
                   pidval,
                   FLUX_ATTRFLAG_IMMUTABLE) < 0)
@@ -791,16 +794,16 @@ static void init_attrs_broker_pid (broker_ctx_t *ctx)
     free (pidval);
 }
 
-static void init_attrs (broker_ctx_t *ctx)
+static void init_attrs (attr_t *attrs, pid_t pid)
 {
     /* Initialize config attrs from environment set up by flux(1)
      */
-    init_attrs_from_environment (ctx->attrs);
+    init_attrs_from_environment (attrs);
 
     /* Initialize other miscellaneous attrs
      */
-    init_attrs_overlay (ctx);
-    init_attrs_broker_pid (ctx);
+    init_attrs_overlay (attrs);
+    init_attrs_broker_pid (attrs, pid);
 }
 
 static void hello_update_cb (hello_t *hello, void *arg)
@@ -1037,7 +1040,7 @@ static int create_persistdir (attr_t *attrs, uint32_t rank)
  *
  * Caller is responsible for freeing memory of returned value.
  */
-static char * calc_endpoint (broker_ctx_t *ctx, const char *endpoint)
+static char * calc_endpoint (attr_t *attrs, const char *endpoint)
 {
     char ipaddr[HOST_NAME_MAX + 1];
     char *ptr, *buf, *rv = NULL;
@@ -1060,7 +1063,7 @@ static char * calc_endpoint (broker_ctx_t *ctx, const char *endpoint)
                 len += strlen (ipaddr);
             }
             else if (*ptr == 'B') {
-                if (attr_get (ctx->attrs, "broker.rundir", &rundir, NULL) < 0) {
+                if (attr_get (attrs, "broker.rundir", &rundir, NULL) < 0) {
                     log_msg ("broker.rundir attribute is not set");
                     goto done;
                 }
@@ -1101,7 +1104,9 @@ static char * calc_endpoint (broker_ctx_t *ctx, const char *endpoint)
     return (rv);
 }
 
-static int boot_pmi (broker_ctx_t *ctx, double *elapsed_sec)
+static int boot_pmi (overlay_t *overlay, attr_t *attrs, int tbon_k,
+                     uint32_t *rank_out, uint32_t *size_out,
+                     double *elapsed_sec)
 {
     int spawned, size, rank, appnum;
     int relay_rank = -1, parent_rank;
@@ -1137,25 +1142,26 @@ static int boot_pmi (broker_ctx_t *ctx, double *elapsed_sec)
         log_msg ("PMI_Get_rank: %s", pmi_strerror (e));
         goto done;
     }
+    *rank_out = (uint32_t)rank;
     if ((e = PMI_Get_appnum (&appnum)) != PMI_SUCCESS) {
         log_msg ("PMI_Get_appnum: %s", pmi_strerror (e));
         goto done;
     }
-    ctx->rank = rank;
-    ctx->size = size;
-    overlay_set_rank (ctx->overlay, ctx->rank);
+    *size_out = (uint32_t)size;
+
+    overlay_set_rank (overlay, (uint32_t)rank);
 
     /* Get id string.
      */
-    if (attr_get (ctx->attrs, "session-id", NULL, NULL) < 0) {
+    if (attr_get (attrs, "session-id", NULL, NULL) < 0) {
         id = xasprintf ("%d", appnum);
-        if (attr_add (ctx->attrs, "session-id", id, FLUX_ATTRFLAG_IMMUTABLE) < 0)
+        if (attr_add (attrs, "session-id", id, FLUX_ATTRFLAG_IMMUTABLE) < 0)
             goto done;
     }
 
     /* Initialize rundir
      */
-    if (create_rundir (ctx->attrs) < 0) {
+    if (create_rundir (attrs) < 0) {
         log_err ("could not initialize rundir");
         goto done;
     }
@@ -1163,34 +1169,34 @@ static int boot_pmi (broker_ctx_t *ctx, double *elapsed_sec)
     /* Set TBON endpoint and mcast endpoint based on user settings
      */
 
-    if (attr_get (ctx->attrs, "tbon.endpoint", &attrtbonendpoint, NULL) < 0) {
+    if (attr_get (attrs, "tbon.endpoint", &attrtbonendpoint, NULL) < 0) {
         log_err ("tbon.endpoint is not set");
         goto done;
     }
 
-    if (!(tbonendpoint = calc_endpoint (ctx, attrtbonendpoint))) {
+    if (!(tbonendpoint = calc_endpoint (attrs, attrtbonendpoint))) {
         log_msg ("calc_endpoint error");
         goto done;
     }
 
-    if (attr_set (ctx->attrs, "tbon.endpoint", tbonendpoint, true) < 0) {
+    if (attr_set (attrs, "tbon.endpoint", tbonendpoint, true) < 0) {
         log_err ("tbon.endpoint could not be set");
         goto done;
     }
 
-    overlay_set_child (ctx->overlay, tbonendpoint);
+    overlay_set_child (overlay, tbonendpoint);
 
-    if (attr_get (ctx->attrs, "mcast.endpoint", &attrmcastendpoint, NULL) < 0) {
+    if (attr_get (attrs, "mcast.endpoint", &attrmcastendpoint, NULL) < 0) {
         log_err ("mcast.endpoint is not set");
         goto done;
     }
 
-    if (!(mcastendpoint = calc_endpoint (ctx, attrmcastendpoint))) {
+    if (!(mcastendpoint = calc_endpoint (attrs, attrmcastendpoint))) {
         log_msg ("calc_endpoint error");
         goto done;
     }
 
-    if (attr_set (ctx->attrs, "mcast.endpoint", mcastendpoint, true) < 0) {
+    if (attr_set (attrs, "mcast.endpoint", mcastendpoint, true) < 0) {
         log_err ("mcast.endpoint could not be set");
         goto done;
     }
@@ -1217,17 +1223,17 @@ static int boot_pmi (broker_ctx_t *ctx, double *elapsed_sec)
             for (i = 0; i < clique_size; i++)
                 if (relay_rank == -1 || clique_ranks[i] < relay_rank)
                     relay_rank = clique_ranks[i];
-            if (relay_rank >= 0 && ctx->rank == relay_rank) {
+            if (relay_rank >= 0 && rank == relay_rank) {
                 const char *rundir;
                 char *relayfile = NULL;
 
-                if (attr_get (ctx->attrs, "broker.rundir", &rundir, NULL) < 0) {
+                if (attr_get (attrs, "broker.rundir", &rundir, NULL) < 0) {
                     log_msg ("broker.rundir attribute is not set");
                     goto done;
                 }
 
                 relayfile = xasprintf ("%s/relay", rundir);
-                overlay_set_relay (ctx->overlay, "ipc://%s", relayfile);
+                overlay_set_relay (overlay, "ipc://%s", relayfile);
                 cleanup_push_string (cleanup_file, relayfile);
                 free (relayfile);
             }
@@ -1260,14 +1266,14 @@ static int boot_pmi (broker_ctx_t *ctx, double *elapsed_sec)
     /* Bind to addresses to expand URI wildcards, so we can exchange
      * the real addresses.
      */
-    if (overlay_bind (ctx->overlay) < 0) {
+    if (overlay_bind (overlay) < 0) {
         log_err ("overlay_bind failed");   /* function is idempotent */
         goto done;
     }
 
     /* Write the URI of downstream facing socket under the rank (if any).
      */
-    if ((child_uri = overlay_get_child (ctx->overlay))) {
+    if ((child_uri = overlay_get_child (overlay))) {
         if (snprintf (key, key_len, "cmbd.%d.uri", rank) >= key_len) {
             log_msg ("pmi key string overflow");
             goto done;
@@ -1286,7 +1292,7 @@ static int boot_pmi (broker_ctx_t *ctx, double *elapsed_sec)
      * (if any).
      */
     if (strcasecmp (mcastendpoint, "tbon")
-        && (relay_uri = overlay_get_relay (ctx->overlay))) {
+        && (relay_uri = overlay_get_relay (overlay))) {
         if (snprintf (key, key_len, "cmbd.%d.relay", rank) >= key_len) {
             log_msg ("pmi key string overflow");
             goto done;
@@ -1314,8 +1320,8 @@ static int boot_pmi (broker_ctx_t *ctx, double *elapsed_sec)
 
     /* Read the uri of our parent, after computing its rank
      */
-    if (ctx->rank > 0) {
-        parent_rank = kary_parentof (ctx->tbon.k, ctx->rank);
+    if (rank > 0) {
+        parent_rank = kary_parentof (tbon_k, (uint32_t)rank);
         if (snprintf (key, key_len, "cmbd.%d.uri", parent_rank) >= key_len) {
             log_msg ("pmi key string overflow");
             goto done;
@@ -1324,7 +1330,7 @@ static int boot_pmi (broker_ctx_t *ctx, double *elapsed_sec)
             log_msg ("pmi_kvs_get: %s", pmi_strerror (e));
             goto done;
         }
-        overlay_set_parent (ctx->overlay, "%s", val);
+        overlay_set_parent (overlay, "%s", val);
     }
 
     /* Event distribution (four configurations):
@@ -1352,9 +1358,9 @@ static int boot_pmi (broker_ctx_t *ctx, double *elapsed_sec)
                 log_msg ("PMI_KVS_Get: %s", pmi_strerror (e));
                 goto done;
             }
-            overlay_set_event (ctx->overlay, "%s", val);
+            overlay_set_event (overlay, "%s", val);
         } else
-            overlay_set_event (ctx->overlay, mcastendpoint);
+            overlay_set_event (overlay, mcastendpoint);
     }
     if ((e = PMI_Barrier ()) != PMI_SUCCESS) {
         log_msg ("PMI_Barrier: %s", pmi_strerror (e));