diff --git a/problem_01/.dockerignore b/problem_01/.dockerignore
new file mode 100644
index 0000000..b83d222
--- /dev/null
+++ b/problem_01/.dockerignore
@@ -0,0 +1 @@
+/target/
diff --git a/problem_01/Cargo.toml b/problem_01/Cargo.toml
index 8f8cb81..9f09bc6 100644
--- a/problem_01/Cargo.toml
+++ b/problem_01/Cargo.toml
@@ -4,6 +4,6 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
-env_logger = "^0.10"
-log = "^0.4"
+env_logger = "0.9.0"
+log = "0.4.0"
 tokio = { version = "1.27.0", features = ["full"] }
diff --git a/problem_01/Dockerfile b/problem_01/Dockerfile
index a6413a6..f878950 100644
--- a/problem_01/Dockerfile
+++ b/problem_01/Dockerfile
@@ -1,22 +1,11 @@
 FROM rust:latest as builder
-
-WORKDIR /usr/src/app
+RUN apt-get update && apt-get -y install ca-certificates cmake musl-tools libssl-dev && rm -rf /var/lib/apt/lists/*
 COPY . .
-# Will build and cache the binary and dependent crates in release mode
-RUN --mount=type=cache,target=/usr/local/cargo,from=rust:latest,source=/usr/local/cargo \
-    --mount=type=cache,target=target \
-    cargo build --release && mv ./target/release/problem_01 ./problem_01
-
-# Runtime image
-FROM debian:bullseye-slim
-
-# Run as "app" user
-RUN useradd -ms /bin/bash app
-
-USER app
-WORKDIR /app
-
-# Get compiled binaries from builder's cargo install directory
-COPY --from=builder /usr/src/app/problem_01 /app/problem_01
-
-# No CMD or ENTRYPOINT, see fly.toml with `cmd` override.
+RUN rustup default stable && rustup update
+RUN rustup target add x86_64-unknown-linux-musl
+ENV PKG_CONFIG_ALLOW_CROSS=1
+RUN cargo build --target x86_64-unknown-linux-musl --release
+FROM scratch
+COPY --from=builder /target/x86_64-unknown-linux-musl/release/problem_01 .
+EXPOSE 8080
+CMD ["/problem_01"]
diff --git a/problem_01/fly.toml b/problem_01/fly.toml
new file mode 100644
index 0000000..9823019
--- /dev/null
+++ b/problem_01/fly.toml
@@ -0,0 +1,20 @@
+# fly.toml app configuration file generated for restless-bush-123 on 2023-04-19T13:36:26+02:00
+#
+# See https://fly.io/docs/reference/configuration/ for information about how to use this file.
+#
+
+app = "restless-bush-123"
+primary_region = "ams"
+
+[experimental]
+  auto_rollback = true
+
+[env]
+  ECHO_PORT = "8080"
+
+[[services]]
+  protocol = "tcp"
+  internal_port = 8080
+
+  [[services.ports]]
+    port = 8080
diff --git a/problem_01/src/main.rs b/problem_01/src/main.rs
index 3fa13b2..3d932e3 100644
--- a/problem_01/src/main.rs
+++ b/problem_01/src/main.rs
@@ -1,21 +1,27 @@
-use tokio::net::TcpListener;
 use tokio::io::{AsyncReadExt, AsyncWriteExt};
+use tokio::net::TcpListener;
 
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
-    let listener = TcpListener::bind("127.0.0.1:4040").await?;
-
+    env_logger::init();
+    let listener = TcpListener::bind("0.0.0.0:8080").await?;
+    log::info!("Start TCP server");
     loop {
         let (mut socket, _) = listener.accept().await?;
 
         tokio::spawn(async move {
             let mut buf = [0; 1024];
-            
-            loop {
 
+            loop {
                 let n = match socket.read(&mut buf).await {
-                    Ok(n) if n == 0 => return,
-                    Ok(n) => n,
+                    Ok(n) if n == 0 => {
+                        log::info!("Receiving echo: {}", n);
+                        return;
+                    }
+                    Ok(n) => {
+                        log::info!("Receiving echo: {}", n);
+                        n
+                    }
                     Err(e) => {
                         log::error!("failed to read from socket; err = {:?}", e);
                         return;