diff --git a/docker/my-dojo/bitcoin/Dockerfile b/docker/my-dojo/bitcoin/Dockerfile
index 1a72b3b..6c6a991 100644
--- a/docker/my-dojo/bitcoin/Dockerfile
+++ b/docker/my-dojo/bitcoin/Dockerfile
@@ -1,4 +1,4 @@
-FROM    debian:buster
+FROM    debian:buster-slim
 
 
 #################################################################
@@ -58,4 +58,4 @@ RUN     chown bitcoin:bitcoin /wait-for-it.sh && \
 
 EXPOSE  8333 9501 9502 28256
 
-USER    bitcoin
\ No newline at end of file
+USER    bitcoin
diff --git a/docker/my-dojo/explorer/Dockerfile b/docker/my-dojo/explorer/Dockerfile
index 4cfe163..b7e8e28 100644
--- a/docker/my-dojo/explorer/Dockerfile
+++ b/docker/my-dojo/explorer/Dockerfile
@@ -1,4 +1,4 @@
-FROM    node:12-buster
+FROM    node:12-alpine
 
 ENV     APP_DIR              /home/node/app
 
@@ -7,8 +7,7 @@ ENV     EXPLORER_VERSION     3.0.0
 
 # Install netcat
 RUN     set -ex && \
-        apt-get update && \
-        apt-get install -y netcat
+        apk --no-cache add bash gcc g++ make python3 git netcat-openbsd
 
 # Download the source code and install it
 RUN     set -ex && \
@@ -29,4 +28,4 @@ RUN     chown node:node "$APP_DIR/restart.sh" && \
 
 EXPOSE  3002
 
-USER    node
\ No newline at end of file
+USER    node
diff --git a/docker/my-dojo/node/Dockerfile b/docker/my-dojo/node/Dockerfile
index 3741ddc..b90e2ba 100644
--- a/docker/my-dojo/node/Dockerfile
+++ b/docker/my-dojo/node/Dockerfile
@@ -1,11 +1,13 @@
-FROM    node:12-buster
+FROM    node:12-alpine
 
 ENV     APP_DIR                 /home/node/app
 ARG     TOR_LINUX_GID
 
+RUN     set -ex && \
+        apk --no-cache add shadow bash gcc g++ make python3
 
 # Add node user to tor group
-RUN     addgroup --system -gid ${TOR_LINUX_GID} tor && \
+RUN     addgroup -S -g ${TOR_LINUX_GID} tor && \
         usermod -a -G tor node
 
 # Install forever
@@ -40,4 +42,4 @@ RUN     chown node:node "$APP_DIR/wait-for-it.sh" && \
         chmod u+x "$APP_DIR/wait-for-it.sh" && \
         chmod g+x "$APP_DIR/wait-for-it.sh"
 
-USER    node
\ No newline at end of file
+USER    node
diff --git a/docker/my-dojo/node/wait-for-it.sh b/docker/my-dojo/node/wait-for-it.sh
index 071c2be..d3a7092 100644
--- a/docker/my-dojo/node/wait-for-it.sh
+++ b/docker/my-dojo/node/wait-for-it.sh
@@ -146,7 +146,11 @@ WAITFORIT_TIMEOUT_PATH=$(type -p timeout)
 WAITFORIT_TIMEOUT_PATH=$(realpath $WAITFORIT_TIMEOUT_PATH 2>/dev/null || readlink -f $WAITFORIT_TIMEOUT_PATH)
 if [[ $WAITFORIT_TIMEOUT_PATH =~ "busybox" ]]; then
         WAITFORIT_ISBUSY=1
-        WAITFORIT_BUSYTIMEFLAG="-t"
+        # Check if busybox timeout uses -t flag
+        # (recent Alpine versions don't support -t anymore)
+        if timeout &>/dev/stdout | grep -q -e '-t '; then
+            WAITFORIT_BUSYTIMEFLAG="-t"
+        fi
 
 else
         WAITFORIT_ISBUSY=0
diff --git a/docker/my-dojo/tor/Dockerfile b/docker/my-dojo/tor/Dockerfile
index 20d39a2..bc884fa 100644
--- a/docker/my-dojo/tor/Dockerfile
+++ b/docker/my-dojo/tor/Dockerfile
@@ -1,4 +1,4 @@
-FROM    debian:buster
+FROM    debian:buster-slim
 
 ENV     TOR_HOME            /var/lib/tor
 ENV     TOR_URL             https://dist.torproject.org
@@ -24,7 +24,7 @@ ARG     TOR_LINUX_GID
 # Install Tor
 RUN     set -ex && \
         apt-get update && \
-        apt-get install -y git libevent-dev zlib1g-dev libssl-dev gcc make automake ca-certificates autoconf musl-dev coreutils gpg wget && \
+        apt-get install -y git libevent-dev zlib1g-dev libssl-dev gcc make automake ca-certificates autoconf musl-dev coreutils gpg wget python3 && \
         mkdir -p /usr/local/src/ && \
         cd /usr/local/src && \
         res=0; \
diff --git a/docker/my-dojo/whirlpool/Dockerfile b/docker/my-dojo/whirlpool/Dockerfile
index b4f0804..3b45d58 100644
--- a/docker/my-dojo/whirlpool/Dockerfile
+++ b/docker/my-dojo/whirlpool/Dockerfile
@@ -1,4 +1,4 @@
-FROM    debian:buster
+FROM    debian:buster-slim
 
 ENV     WHIRLPOOL_HOME                /home/whirlpool
 ENV     WHIRLPOOL_DIR                 /usr/local/whirlpool-cli
@@ -8,8 +8,12 @@ ARG     WHIRLPOOL_LINUX_GID
 
 # Install prerequisites
 # Create group & user whirlpool
+# Create /usr/share/man/man1 directory
 # Create .whirlpool-cli subdirectory of WHIRLPOOL_HOME
 # Create /usr/local/src/whirlpool-cli directory
+
+RUN     mkdir -p /usr/share/man/man1
+
 RUN     set -ex && \
         apt-get update && \
         apt-get install -y libevent-dev zlib1g-dev libssl-dev gcc make automake ca-certificates autoconf musl-dev coreutils gpg wget default-jdk && \