diff --git a/cmd/karma/assets.go b/cmd/karma/assets.go
index d40ff1404..70fc9c887 100644
--- a/cmd/karma/assets.go
+++ b/cmd/karma/assets.go
@@ -2,9 +2,9 @@ package main
 
 import (
 	"io"
-	"io/ioutil"
 	"mime"
 	"net/http"
+	"os"
 	"path/filepath"
 	"strings"
 	"time"
@@ -26,7 +26,7 @@ func serveFileOr404(path string, contentType string) http.HandlerFunc {
 			_, _ = w.Write([]byte{})
 			return
 		}
-		data, err := ioutil.ReadFile(path)
+		data, err := os.ReadFile(path)
 		if err != nil {
 			contentText(w)
 			w.WriteHeader(http.StatusNotFound)
diff --git a/cmd/karma/benchmark_test.go b/cmd/karma/benchmark_test.go
index 51da00201..191dc538e 100644
--- a/cmd/karma/benchmark_test.go
+++ b/cmd/karma/benchmark_test.go
@@ -1,9 +1,10 @@
 package main
 
 import (
+	"bytes"
 	"fmt"
-	"io/ioutil"
 	"net/http/httptest"
+	"os"
 	"runtime"
 	"testing"
 
@@ -23,14 +24,14 @@ func reportMemoryMetrics(b *testing.B) {
 func BenchmarkCompress(b *testing.B) {
 	zerolog.SetGlobalLevel(zerolog.FatalLevel)
 
-	data, err := ioutil.ReadFile("./tests/compress/alerts.json")
+	data, err := os.ReadFile("./tests/compress/alerts.json")
 	if err != nil {
 		b.Errorf("Failed to read data: %s", err.Error())
 	}
 
 	b.Run("Run", func(b *testing.B) {
 		for i := 0; i < b.N; i++ {
-			compressed, err := compressResponse(data)
+			compressed, err := compressResponse(data, nil)
 			if err != nil {
 				b.Errorf("Failed to compress data: %s", err.Error())
 			}
@@ -48,19 +49,19 @@ func BenchmarkCompress(b *testing.B) {
 func BenchmarkDecompress(b *testing.B) {
 	zerolog.SetGlobalLevel(zerolog.FatalLevel)
 
-	data, err := ioutil.ReadFile("./tests/compress/alerts.json")
+	data, err := os.ReadFile("./tests/compress/alerts.json")
 	if err != nil {
 		b.Errorf("Failed to read data: %s", err.Error())
 	}
 
-	compressed, err := compressResponse(data)
+	compressed, err := compressResponse(data, nil)
 	if err != nil {
 		b.Errorf("Failed to compress data: %s", err.Error())
 	}
 
 	b.Run("Run", func(b *testing.B) {
 		for i := 0; i < b.N; i++ {
-			_, err := decompressCachedResponse(compressed)
+			_, err := decompressCachedResponse(bytes.NewReader(compressed))
 			if err != nil {
 				b.Errorf("Failed to decompress data: %s", err.Error())
 			}
@@ -75,19 +76,19 @@ func BenchmarkDecompress(b *testing.B) {
 func BenchmarkCompressionAndDecompression(b *testing.B) {
 	zerolog.SetGlobalLevel(zerolog.FatalLevel)
 
-	data, err := ioutil.ReadFile("./tests/compress/alerts.json")
+	data, err := os.ReadFile("./tests/compress/alerts.json")
 	if err != nil {
 		b.Errorf("Failed to read data: %s", err.Error())
 	}
 
 	b.Run("Run", func(b *testing.B) {
 		for i := 0; i < b.N; i++ {
-			compressed, err := compressResponse(data)
+			compressed, err := compressResponse(data, nil)
 			if err != nil {
 				b.Errorf("Failed to compress data: %s", err.Error())
 			}
 
-			_, err = decompressCachedResponse(compressed)
+			_, err = decompressCachedResponse(bytes.NewReader(compressed))
 			if err != nil {
 				b.Errorf("Failed to decompress data: %s", err.Error())
 			}
diff --git a/cmd/karma/main.go b/cmd/karma/main.go
index a463e28d5..2df98aa6a 100644
--- a/cmd/karma/main.go
+++ b/cmd/karma/main.go
@@ -6,7 +6,6 @@ import (
 	"errors"
 	"fmt"
 	"html/template"
-	"io/ioutil"
 	"mime"
 	"net"
 	"net/http"
@@ -404,7 +403,7 @@ func writePidFile() error {
 	if pidFile != "" {
 		log.Info().Str("path", pidFile).Msg("Writing PID file")
 		pid := os.Getpid()
-		err := ioutil.WriteFile(pidFile, []byte(strconv.Itoa(pid)), 0644)
+		err := os.WriteFile(pidFile, []byte(strconv.Itoa(pid)), 0644)
 		if err != nil {
 			return fmt.Errorf("failed to write a PID file: %s", err)
 		}
diff --git a/cmd/karma/proxy.go b/cmd/karma/proxy.go
index 73c6a0a5d..82d8ae98b 100644
--- a/cmd/karma/proxy.go
+++ b/cmd/karma/proxy.go
@@ -3,7 +3,7 @@ package main
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"net/http/httputil"
 	"net/url"
@@ -85,7 +85,7 @@ func handlePostRequest(alertmanager *alertmanager.Alertmanager, h http.Handler)
 			Msg("Proxy request")
 
 		defer r.Body.Close()
-		body, err := ioutil.ReadAll(r.Body)
+		body, err := io.ReadAll(r.Body)
 		if err != nil {
 			log.Error().Err(err).
 				Str("alertmanager", alertmanager.Name).
@@ -153,11 +153,11 @@ func handlePostRequest(alertmanager *alertmanager.Alertmanager, h http.Handler)
 				return
 			}
 
-			r.Body = ioutil.NopCloser(bytes.NewBuffer(newBody))
+			r.Body = io.NopCloser(bytes.NewBuffer(newBody))
 			r.ContentLength = int64(len(newBody))
 			r.Header.Set("Content-Length", fmt.Sprintf("%d", r.ContentLength))
 		} else {
-			r.Body = ioutil.NopCloser(bytes.NewBuffer(body))
+			r.Body = io.NopCloser(bytes.NewBuffer(body))
 		}
 
 		h.ServeHTTP(w, r)
diff --git a/cmd/karma/proxy_test.go b/cmd/karma/proxy_test.go
index a78516087..685d224e3 100644
--- a/cmd/karma/proxy_test.go
+++ b/cmd/karma/proxy_test.go
@@ -4,7 +4,7 @@ import (
 	"bytes"
 	"errors"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"net/http/httptest"
 	"regexp"
@@ -535,11 +535,11 @@ func TestProxyUserRewrite(t *testing.T) {
 				_ = am.Pull()
 
 				httpmock.RegisterResponder("POST", "http://localhost/api/v2/silences", func(req *http.Request) (*http.Response, error) {
-					body, _ := ioutil.ReadAll(req.Body)
+					body, _ := io.ReadAll(req.Body)
 					return httpmock.NewBytesResponse(200, body), nil
 				})
 
-				req := httptest.NewRequest("POST", "/proxy/alertmanager/proxyAuth/api/v2/silences", ioutil.NopCloser(bytes.NewBufferString(testCase.frontednRequestBody)))
+				req := httptest.NewRequest("POST", "/proxy/alertmanager/proxyAuth/api/v2/silences", io.NopCloser(bytes.NewBufferString(testCase.frontednRequestBody)))
 				for k, v := range testCase.requestHeaders {
 					req.Header.Set(k, v)
 				}
@@ -551,7 +551,7 @@ func TestProxyUserRewrite(t *testing.T) {
 					t.Errorf("Got response code %d instead of %d", resp.Code, testCase.responseCode)
 				}
 
-				gotBody, _ := ioutil.ReadAll(resp.Body)
+				gotBody, _ := io.ReadAll(resp.Body)
 				if string(gotBody) != testCase.proxyRequestBody {
 					diff := difflib.UnifiedDiff{
 						A:        difflib.SplitLines(testCase.proxyRequestBody),
@@ -1193,11 +1193,11 @@ func TestProxySilenceACL(t *testing.T) {
 				_ = am.Pull()
 
 				httpmock.RegisterResponder("POST", "http://localhost/api/v2/silences", func(req *http.Request) (*http.Response, error) {
-					body, _ := ioutil.ReadAll(req.Body)
+					body, _ := io.ReadAll(req.Body)
 					return httpmock.NewBytesResponse(200, body), nil
 				})
 
-				req := httptest.NewRequest("POST", "/proxy/alertmanager/proxyACL/api/v2/silences", ioutil.NopCloser(bytes.NewBufferString(testCase.frontednRequestBody)))
+				req := httptest.NewRequest("POST", "/proxy/alertmanager/proxyACL/api/v2/silences", io.NopCloser(bytes.NewBufferString(testCase.frontednRequestBody)))
 				req.Header.Set("X-User", testCase.requestUsername)
 
 				resp := newCloseNotifyingRecorder()
@@ -1246,7 +1246,7 @@ func TestProxyRequestReadFailure(t *testing.T) {
 			t.Errorf("Got response code %d instead of 500", resp.Code)
 		}
 
-		gotBody, _ := ioutil.ReadAll(resp.Body)
+		gotBody, _ := io.ReadAll(resp.Body)
 		if string(gotBody) != "request read error\n" {
 			t.Errorf("Body mismatch:\n%s", gotBody)
 		}
@@ -1299,7 +1299,7 @@ func TestProxyRequestToUnsupportedAlertmanager(t *testing.T) {
 		return
 	}
 
-	req := httptest.NewRequest("POST", "/proxy/alertmanager/proxyToUnsupported/api/v2/silences", ioutil.NopCloser(bytes.NewBufferString(`{}`)))
+	req := httptest.NewRequest("POST", "/proxy/alertmanager/proxyToUnsupported/api/v2/silences", io.NopCloser(bytes.NewBufferString(`{}`)))
 
 	resp := newCloseNotifyingRecorder()
 	r.ServeHTTP(resp, req)
@@ -1307,7 +1307,7 @@ func TestProxyRequestToUnsupportedAlertmanager(t *testing.T) {
 		t.Errorf("Got response code %d instead of 500", resp.Code)
 	}
 
-	gotBody, _ := ioutil.ReadAll(resp.Body)
+	gotBody, _ := io.ReadAll(resp.Body)
 	if string(gotBody) != "can't find silence mapper for Alertmanager 0.1.0\n" {
 		t.Errorf("Body mismatch:\n%s", gotBody)
 	}
diff --git a/cmd/karma/tests/testscript/096_tls_client.txt b/cmd/karma/tests/testscript/096_tls_client.txt
index 4506121a9..1d722d653 100644
--- a/cmd/karma/tests/testscript/096_tls_client.txt
+++ b/cmd/karma/tests/testscript/096_tls_client.txt
@@ -92,7 +92,6 @@ import (
 	"crypto/tls"
 	"crypto/x509"
 	"io"
-	"io/ioutil"
 	"log"
 	"net"
 	"net/http"
@@ -136,7 +135,7 @@ func empty(w http.ResponseWriter, r *http.Request) {
 
 func main() {
 	pid := os.Getpid()
-	err := ioutil.WriteFile("alertmanager.pid", []byte(strconv.Itoa(pid)), 0644)
+	err := os.WriteFile("alertmanager.pid", []byte(strconv.Itoa(pid)), 0644)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -146,7 +145,7 @@ func main() {
 	http.HandleFunc("/api/v2/silences", empty)
 	http.HandleFunc("/api/v2/alerts/groups", empty)
 
-	caCert, err := ioutil.ReadFile("ca.pem")
+	caCert, err := os.ReadFile("ca.pem")
 	if err != nil {
 		log.Fatal(err)
 	}
diff --git a/cmd/karma/views.go b/cmd/karma/views.go
index 05033464a..087bc643d 100644
--- a/cmd/karma/views.go
+++ b/cmd/karma/views.go
@@ -6,7 +6,7 @@ import (
 	"encoding/base64"
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"sort"
 	"strings"
@@ -45,10 +45,13 @@ func robots(w http.ResponseWriter, r *http.Request) {
 	_, _ = w.Write([]byte("User-agent: *\nDisallow: /\n"))
 }
 
-func compressResponse(data []byte) ([]byte, error) {
+func compressResponse(data []byte, gz io.WriteCloser) ([]byte, error) {
 	var b bytes.Buffer
-	// this only fails if we pass unsupported level (3 is valid)
-	gz, _ := gzip.NewWriterLevel(&b, 3)
+
+	if gz == nil {
+		// this only fails if we pass unsupported level (3 is valid)
+		gz, _ = gzip.NewWriterLevel(&b, 3)
+	}
 
 	_, err := gz.Write(data)
 	if err != nil {
@@ -70,16 +73,16 @@ func compressResponse(data []byte) ([]byte, error) {
 	return compressed, nil
 }
 
-func decompressCachedResponse(data []byte) ([]byte, error) {
-	b := bytes.NewReader(data)
-	z, err := gzip.NewReader(b)
+func decompressCachedResponse(r io.Reader) ([]byte, error) {
+	z, err := gzip.NewReader(r)
 	if err != nil {
 		return nil, fmt.Errorf("failed to created new compression reader: %s", err.Error())
 	}
-	p, err := ioutil.ReadAll(z)
+	p, err := io.ReadAll(z)
 	if err != nil {
 		return nil, fmt.Errorf("failed to decompress data: %s", err.Error())
 	}
+	z.Close()
 	return p, nil
 }
 
@@ -188,7 +191,8 @@ func alerts(w http.ResponseWriter, r *http.Request) {
 
 	data, found := apiCache.Get(cacheKey)
 	if found {
-		rawData, _ := decompressCachedResponse(data.([]byte))
+		r := bytes.NewReader(data.([]byte))
+		rawData, _ := decompressCachedResponse(r)
 		// need to overwrite settings as they can have user specific data
 		newResp := models.AlertsResponse{}
 		_ = json.Unmarshal(rawData, &newResp)
@@ -483,7 +487,7 @@ func alerts(w http.ResponseWriter, r *http.Request) {
 	resp.Receivers = receivers
 
 	data, _ = json.Marshal(resp)
-	compressedData, _ := compressResponse(data.([]byte))
+	compressedData, _ := compressResponse(data.([]byte), nil)
 	apiCache.Set(cacheKey, compressedData, -1)
 
 	mimeJSON(w)
diff --git a/cmd/karma/views_test.go b/cmd/karma/views_test.go
index e0f17f825..14bc2810f 100644
--- a/cmd/karma/views_test.go
+++ b/cmd/karma/views_test.go
@@ -1,8 +1,10 @@
 package main
 
 import (
+	"bytes"
 	"context"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"net/http"
 	"net/http/httptest"
@@ -2574,3 +2576,76 @@ func TestAlertFilters(t *testing.T) {
 		}
 	}
 }
+
+type gzErrWriter struct {
+	failWrite bool
+	failClose bool
+}
+
+func (ew *gzErrWriter) Write(p []byte) (n int, err error) {
+	if ew.failWrite {
+		return 0, errors.New("Write error")
+	}
+	return len(p), nil
+}
+func (ew *gzErrWriter) Close() error {
+	if ew.failClose {
+		return errors.New("Close error")
+	}
+	return nil
+}
+
+func TestCompressResponseWriteError(t *testing.T) {
+	_, err := compressResponse(nil, &gzErrWriter{failWrite: true})
+	if err == nil {
+		t.Error("compressResponse() didn't return any error")
+	}
+}
+
+func TestCompressResponseCloseError(t *testing.T) {
+	_, err := compressResponse(nil, &gzErrWriter{failClose: true})
+	if err == nil {
+		t.Error("compressResponse() didn't return any error")
+	}
+}
+
+type gzErrReader struct {
+	failAfter int
+	reads     int
+}
+
+func (er *gzErrReader) Read(p []byte) (n int, err error) {
+	if er.reads >= er.failAfter {
+		return 0, errors.New("Read error")
+	}
+	er.reads++
+
+	b, err := compressResponse([]byte("abcd"), nil)
+	if err != nil {
+		return 0, err
+	}
+
+	return bytes.NewReader(b).Read(p)
+}
+
+func TestDecompressResponseResetError(t *testing.T) {
+	_, err := decompressCachedResponse(&gzErrReader{failAfter: 0})
+	if err == nil {
+		t.Error("decompressCachedResponse() didn't return any error")
+		return
+	}
+	if err.Error() != "failed to created new compression reader: Read error" {
+		t.Errorf("decompressCachedResponse() returned wrong error: %s", err)
+	}
+}
+
+func TestDecompressResponseReadError(t *testing.T) {
+	_, err := decompressCachedResponse(&gzErrReader{failAfter: 1})
+	if err == nil {
+		t.Error("decompressCachedResponse() didn't return any error")
+		return
+	}
+	if err.Error() != "failed to decompress data: Read error" {
+		t.Errorf("decompressCachedResponse() returned wrong error: %s", err)
+	}
+}
diff --git a/internal/alertmanager/tls.go b/internal/alertmanager/tls.go
index 10e53256b..44ba11132 100644
--- a/internal/alertmanager/tls.go
+++ b/internal/alertmanager/tls.go
@@ -3,8 +3,8 @@ package alertmanager
 import (
 	"crypto/tls"
 	"crypto/x509"
-	"io/ioutil"
 	"net/http"
+	"os"
 
 	"github.com/rs/zerolog/log"
 )
@@ -13,7 +13,7 @@ func configureTLSRootCAs(tlsConfig *tls.Config, caPath string) error {
 	log.Debug().
 		Str("path", caPath).
 		Msg("Loading TLS CA cert")
-	caCert, err := ioutil.ReadFile(caPath)
+	caCert, err := os.ReadFile(caPath)
 	if err != nil {
 		return err
 	}
diff --git a/internal/config/acl.go b/internal/config/acl.go
index 0bf2710fd..9f9215ad8 100644
--- a/internal/config/acl.go
+++ b/internal/config/acl.go
@@ -2,7 +2,7 @@ package config
 
 import (
 	"fmt"
-	"io/ioutil"
+	"os"
 
 	yaml "gopkg.in/yaml.v2"
 )
@@ -47,7 +47,7 @@ type silencesACLSchema struct {
 func ReadSilenceACLConfig(path string) (*silencesACLSchema, error) {
 	cfg := silencesACLSchema{}
 
-	f, err := ioutil.ReadFile(path)
+	f, err := os.ReadFile(path)
 	if err != nil {
 		return nil, fmt.Errorf("failed to load silence ACL configuration file %q: %v", path, err)
 	}
diff --git a/internal/config/config.go b/internal/config/config.go
index fb075279b..62665ee83 100644
--- a/internal/config/config.go
+++ b/internal/config/config.go
@@ -4,7 +4,6 @@ import (
 	"bufio"
 	"bytes"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"strings"
 	"time"
@@ -130,7 +129,7 @@ func SetupFlags(f *pflag.FlagSet) {
 }
 
 func validateConfigFile(path string) error {
-	f, err := ioutil.ReadFile(path)
+	f, err := os.ReadFile(path)
 	if err != nil {
 		return err
 	}
diff --git a/internal/mock/mock.go b/internal/mock/mock.go
index a65e13e20..75e8d0436 100644
--- a/internal/mock/mock.go
+++ b/internal/mock/mock.go
@@ -1,7 +1,6 @@
 package mock
 
 import (
-	"io/ioutil"
 	"os"
 	"path"
 	"path/filepath"
@@ -20,7 +19,7 @@ func GetAbsoluteMockPath(filename string, version string) string {
 // GetMockResponder returns a httpmock.Responder for given file/version
 func GetMockResponder(url string, version string, filename string) httpmock.Responder {
 	fullPath := GetAbsoluteMockPath(filename, version)
-	mockJSON, _ := ioutil.ReadFile(fullPath)
+	mockJSON, _ := os.ReadFile(fullPath)
 	return httpmock.NewBytesResponder(200, mockJSON)
 }
 
@@ -34,7 +33,7 @@ func ListAllMocks() []string {
 	_, f, _, _ := runtime.Caller(0)
 	cwd := filepath.Dir(f)
 
-	dirents, _ := ioutil.ReadDir(cwd)
+	dirents, _ := os.ReadDir(cwd)
 	dirs := []string{}
 	for _, dirent := range dirents {
 		if dirent.IsDir() {