diff --git a/.github/workflows/golangci-lint.yml b/.github/workflows/golangci-lint.yml
index 4146730..d1a7611 100644
--- a/.github/workflows/golangci-lint.yml
+++ b/.github/workflows/golangci-lint.yml
@@ -9,7 +9,7 @@ on:
 jobs:
   golangci:
     name: golangci-lint
-    runs-on: ubuntu-latest
+    runs-on: blacksmith-4vcpu-ubuntu-2404
     steps:
       - uses: actions/setup-go@v3
         with:
diff --git a/.github/workflows/idle_timer.yml b/.github/workflows/idle_timer.yml
index 49aa65c..040779b 100644
--- a/.github/workflows/idle_timer.yml
+++ b/.github/workflows/idle_timer.yml
@@ -9,7 +9,7 @@ on:
 jobs:
   idletimer:
     name: idle-timer
-    runs-on: ubuntu-latest
+    runs-on: blacksmith-4vcpu-ubuntu-2404
     timeout-minutes: 5
     steps:
       - uses: actions/setup-go@v3
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 40d5177..2c3409d 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -8,7 +8,10 @@ on:
 jobs:
   linux:
     name: create linux binaries
-    runs-on: ubuntu-20.04
+    # Use the oldest available Ubuntu image to keep the glibc version low for the
+    # published, dynamically-linked (cgo, non-static) linux-x86_64 binary. Building
+    # on a newer image would raise the glibc floor and break older target systems.
+    runs-on: blacksmith-4vcpu-ubuntu-2204
     steps:
       - name: checkout code
         uses: actions/checkout@v3
@@ -37,7 +40,7 @@ jobs:
 
   mac:
     name: create mac binaries
-    runs-on: macos-11
+    runs-on: blacksmith-6vcpu-macos-15
     steps:
       - name: checkout
         uses: actions/checkout@v3
diff --git a/cache/grpcproxy/grpcproxy_test.go b/cache/grpcproxy/grpcproxy_test.go
index 7a1abc8..ba82977 100644
--- a/cache/grpcproxy/grpcproxy_test.go
+++ b/cache/grpcproxy/grpcproxy_test.go
@@ -244,7 +244,7 @@ func newFixture(t *testing.T, proxy cache.Proxy, storageMode string) *fixture {
 	go func() {
 		err := server.ServeGRPC(listener, grpcServer, false, false, true, diskCache, logger, logger)
 		if err != nil {
-			logger.Printf(err.Error())
+			logger.Print(err.Error())
 		}
 	}()