rpk: supports triggering on-demand balancer

src/go/rpk/go.mod

@@ -37,7 +37,7 @@ require (
 	github.com/pkg/errors v0.9.1
 	github.com/prometheus/client_model v0.6.1
 	github.com/prometheus/common v0.55.0
-	github.com/redpanda-data/common-go/rpadmin v0.1.3
+	github.com/redpanda-data/common-go/rpadmin v0.1.4
 	github.com/rs/xid v1.5.0
 	github.com/safchain/ethtool v0.4.1
 	github.com/santhosh-tekuri/jsonschema/v6 v6.0.1

src/go/rpk/go.sum

@@ -208,8 +208,8 @@ github.com/prometheus/common v0.55.0 h1:KEi6DK7lXW/m7Ig5i47x0vRzuBsHuvJdi5ee6Y3G
 github.com/prometheus/common v0.55.0/go.mod h1:2SECS4xJG1kd8XF9IcM1gMX6510RAEL65zxzNImwdc8=
 github.com/redpanda-data/common-go/net v0.1.0 h1:JnJioRJuL961r1QXiJQ1tW9+yEaJfu8FpXnUmvQbwNM=
 github.com/redpanda-data/common-go/net v0.1.0/go.mod h1:iOdNkjxM7a1T8F3cYHTaKIPFCHzzp/ia6TN+Z+7Tt5w=
-github.com/redpanda-data/common-go/rpadmin v0.1.3 h1:JRdr4rHcdr+A0hHr+viJYnPm+dP01bsgVUoQLM7Kz44=
-github.com/redpanda-data/common-go/rpadmin v0.1.3/go.mod h1:I7umqhnMhIOSEnIA3fvLtdQU7QO/SbWGCwFfFDs3De4=
+github.com/redpanda-data/common-go/rpadmin v0.1.4 h1:NkVvurQRmBT9r58UVezC0DhYjR3vzYkQnkFndJBb5xE=
+github.com/redpanda-data/common-go/rpadmin v0.1.4/go.mod h1:I7umqhnMhIOSEnIA3fvLtdQU7QO/SbWGCwFfFDs3De4=
 github.com/redpanda-data/go-avro/v2 v2.0.0-20240405204525-77b1144dc525 h1:vskZrV6q8W8flL0Ud23AJUYAd8ZgTadO45+loFnG2G0=
 github.com/redpanda-data/go-avro/v2 v2.0.0-20240405204525-77b1144dc525/go.mod h1:3YqAM7pgS5vW/EH7naCjFqnAajSgi0f0CfMe1HGhLxQ=
 github.com/rivo/uniseg v0.4.7 h1:WUdvkW8uEhrYfLC4ZzdpI2ztxP1I582+49Oc5Mq64VQ=

src/go/rpk/pkg/cli/cluster/partitions/balancer_run.go

@@ -0,0 +1,67 @@
+// Copyright 2024 Redpanda Data, Inc.
+//
+// Use of this software is governed by the Business Source License
+// included in the file licenses/BSL.md
+//
+// As of the Change Date specified in that file, in accordance with
+// the Business Source License, use of this software will be governed
+// by the Apache License, Version 2.0
+
+package partitions
+
+import (
+	"fmt"
+
+	"github.com/redpanda-data/redpanda/src/go/rpk/pkg/adminapi"
+	"github.com/redpanda-data/redpanda/src/go/rpk/pkg/config"
+	"github.com/redpanda-data/redpanda/src/go/rpk/pkg/out"
+	"github.com/spf13/afero"
+	"github.com/spf13/cobra"
+)
+
+func newTriggerBalancerCommand(fs afero.Fs, p *config.Params) *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "balance",
+		Short: "Triggers on-demand partition balancing",
+		Long: `Triggers on-demand partition balancing.
+
+This command allows you to trigger on-demand partition balancing.
+
+With Redpanda Community Edition, the partition count on each broker
+can easily become uneven, which leads to data skewing. To distribute
+partitions across brokers, you can run this command to trigger
+on-demand partition balancing.
+
+With Redpanda Enterprise Edition, Continuous Data Balancing monitors
+broker and rack availability, as well as disk usage, to avoid topic
+hotspots. However, there are edge cases where users should manually
+trigger partition balancing (such as a node becoming unavailable for
+a prolonged time and rejoining the cluster thereafter). In such cases,
+you should run this command to trigger partition balancing manually.
+
+After you run this command, monitor the balancer progress using:
+
+    rpk cluster partitions balancer-status
+
+To see more detailed movement status, monitor the progress using:
+
+    rpk cluster partitions move-status
+`,
+
+		Args: cobra.ExactArgs(0),
+		Run: func(cmd *cobra.Command, args []string) {
+			p, err := p.LoadVirtualProfile(fs)
+			out.MaybeDie(err, "rpk unable to load config: %v", err)
+			config.CheckExitCloudAdmin(p)
+
+			cl, err := adminapi.NewClient(fs, p)
+			out.MaybeDie(err, "unable to initialize admin client: %v", err)
+
+			err = cl.TriggerBalancer(cmd.Context())
+			out.MaybeDie(err, "failed to invoke on-demand partition balancing: %v", err)
+
+			fmt.Println("Successfully triggered on-demand partition balancing.\n\nPlease find the progress with 'rpk cluster partitions balancer-status'.")
+		},
+	}
+	return cmd
+}

src/go/rpk/pkg/cli/cluster/partitions/partitions.go

@@ -33,6 +33,7 @@ func NewPartitionsCommand(fs afero.Fs, p *config.Params) *cobra.Command {
 		newPartitionEnableCommand(fs, p),
 		newPartitionMovementsStatusCommand(fs, p),
 		newTransferLeaderCommand(fs, p),
+		newTriggerBalancerCommand(fs, p),
 		newUnsafeRecoveryCommand(fs, p),
 	)
 	return cmd