diff --git a/src/Container/GenericContainer.php b/src/Container/GenericContainer.php
index 9a0a266..ca0ba6f 100644
--- a/src/Container/GenericContainer.php
+++ b/src/Container/GenericContainer.php
@@ -232,10 +232,12 @@ class GenericContainer implements TestContainer
             $this->id = $containerCreateResponse?->getId() ?? '';
         } catch (ContainerCreateNotFoundException) {
             /** @var CreateImageStream $imageCreateResponse */
-            $this->dockerClient->imageCreate(null, [
+            $imageCreateResponse = $this->dockerClient->imageCreate(null, [
                 'fromImage' => explode(':', $this->image)[0],
                 'tag' => explode(':', $this->image)[1] ?? 'latest',
             ]);
+            $imageCreateResponse->wait();
+
             return $this->start();
         }
 
diff --git a/src/Container/MariaDBContainer.php b/src/Container/MariaDBContainer.php
index 72f0aac..b806783 100644
--- a/src/Container/MariaDBContainer.php
+++ b/src/Container/MariaDBContainer.php
@@ -4,7 +4,7 @@ declare(strict_types=1);
 
 namespace Testcontainers\Container;
 
-use Testcontainers\Wait\WaitForLog;
+use Testcontainers\Wait\WaitForExec;
 
 /**
  * Left for namespace backward compatibility
@@ -17,8 +17,12 @@ class MariaDBContainer extends Container
     {
         parent::__construct('mariadb:' . $version);
         $this->withExposedPorts(3306);
-        $this->withWait(new WaitForLog('ready for connections'));
         $this->withEnvironment('MARIADB_ROOT_PASSWORD', $mysqlRootPassword);
+        $this->withWait(new WaitForExec([
+            "mariadb-admin",
+            "ping",
+            "-h", "127.0.0.1",
+        ]));
     }
 
     public static function make(string $version = 'latest', string $mysqlRootPassword = 'root'): self
@@ -40,4 +44,4 @@ class MariaDBContainer extends Container
 
         return $this;
     }
-}
\ No newline at end of file
+}
diff --git a/src/Container/MySQLContainer.php b/src/Container/MySQLContainer.php
index 232c912..a6e7efb 100644
--- a/src/Container/MySQLContainer.php
+++ b/src/Container/MySQLContainer.php
@@ -4,7 +4,7 @@ declare(strict_types=1);
 
 namespace Testcontainers\Container;
 
-use Testcontainers\Wait\WaitForLog;
+use Testcontainers\Wait\WaitForExec;
 
 /**
  * Left for namespace backward compatibility
@@ -18,7 +18,11 @@ class MySQLContainer extends Container
         parent::__construct('mysql:' . $version);
         $this->withExposedPorts(3306);
         $this->withEnvironment('MYSQL_ROOT_PASSWORD', $mysqlRootPassword);
-        $this->withWait(new WaitForLog('ready for connections'));
+        $this->withWait(new WaitForExec([
+            "mysqladmin",
+            "ping",
+            "-h", "127.0.0.1",
+        ]));
     }
 
     public static function make(string $version = 'latest', string $mysqlRootPassword = 'root'): self
diff --git a/src/Container/StartedGenericContainer.php b/src/Container/StartedGenericContainer.php
index 60d478c..ec81e71 100644
--- a/src/Container/StartedGenericContainer.php
+++ b/src/Container/StartedGenericContainer.php
@@ -6,10 +6,10 @@ namespace Testcontainers\Container;
 
 use Docker\API\Client;
 use Docker\API\Model\ContainersIdExecPostBody;
-use Docker\API\Model\ContainersIdJsonGetResponse200;
 use Docker\API\Model\IdResponse;
 use Docker\API\Runtime\Client\Client as DockerRuntimeClient;
 use Docker\Docker;
+use Psr\Http\Message\ResponseInterface;
 use Testcontainers\ContainerClient\DockerContainerClient;
 
 class StartedGenericContainer implements StartedTestContainer
@@ -53,7 +53,7 @@ class StartedGenericContainer implements StartedTestContainer
         /** @var IdResponse | null $exec */
         $exec = $this->dockerClient->containerExec($this->id, $execConfig);
 
-        if($exec === null || $exec->getId() === null) {
+        if ($exec === null || $exec->getId() === null) {
             throw new \RuntimeException('Failed to create exec command');
         }
 
@@ -108,17 +108,36 @@ class StartedGenericContainer implements StartedTestContainer
         return $this->inspect()->ports[$port];
     }
 
-    //TODO: not ready yet
+    /**
+     * @throws \JsonException
+     */
     public function getFirstMappedPort(): int
     {
-        /** @var ContainersIdJsonGetResponse200 | null $containerInspectResponse */
-        $containerInspectResponse =  $this->dockerClient->containerInspect($this->id);
-        $settings = $containerInspectResponse->getNetworkSettings();
+        //For some reason, containerInspect can crash when using FETCH_OBJECT option (e.g. with OpenSearch)
+        //should be checked within beluga-php/docker-php client library
+        /** @var ResponseInterface | null $containerInspectResponse */
+        $containerInspectResponse =  $this->dockerClient->containerInspect($this->id, [], Docker::FETCH_RESPONSE);
+        if ($containerInspectResponse === null) {
+            throw new \RuntimeException('Failed to inspect container');
+        }
+
+        $containerInspectResponseAsArray = json_decode(
+            $containerInspectResponse->getBody()->getContents(),
+            true,
+            512,
+            JSON_THROW_ON_ERROR
+        );
+
+        /** @var array<string, array<array<string, string>>> $ports */
+        $ports = $containerInspectResponseAsArray['NetworkSettings']['Ports'] ?? [];
+
+        if ($ports === []) {
+            throw new \RuntimeException('Failed to get ports from container');
+        }
 
-        $ports = (array)$settings->getPorts();
         $port = array_key_first($ports);
 
-        return (int) $ports[$port][0]->getHostPort();
+        return (int) $ports[$port][0]['HostPort'];
     }
 
     public function getName(): string
diff --git a/src/ContainerClient/DockerContainerClient.php b/src/ContainerClient/DockerContainerClient.php
index 84bf645..8001992 100644
--- a/src/ContainerClient/DockerContainerClient.php
+++ b/src/ContainerClient/DockerContainerClient.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Testcontainers\ContainerClient;
 
 use Docker\Docker as DockerClient;
@@ -11,9 +13,6 @@ class DockerContainerClient
      */
     private static ?DockerClient $dockerClient = null;
 
-    /**
-     * Private constructor to prevent creating instance outside the class.
-     */
     private function __construct()
     {
     }
diff --git a/src/Modules/MariaDBContainer.php b/src/Modules/MariaDBContainer.php
index 07ea973..a45ffb3 100644
--- a/src/Modules/MariaDBContainer.php
+++ b/src/Modules/MariaDBContainer.php
@@ -5,7 +5,7 @@ declare(strict_types=1);
 namespace Testcontainers\Modules;
 
 use Testcontainers\Container\GenericContainer;
-use Testcontainers\Wait\WaitForLog;
+use Testcontainers\Wait\WaitForExec;
 
 class MariaDBContainer extends GenericContainer
 {
@@ -13,8 +13,12 @@ class MariaDBContainer extends GenericContainer
     {
         parent::__construct('mariadb:' . $version);
         $this->withExposedPorts(3306);
-        $this->withWait(new WaitForLog('ready for connections'));
         $this->withEnvironment('MARIADB_ROOT_PASSWORD', $mysqlRootPassword);
+        $this->withWait(new WaitForExec([
+            "mariadb-admin",
+            "ping",
+            "-h", "127.0.0.1",
+        ]));
     }
 
     public function withMariaDBUser(string $username, string $password): self
diff --git a/src/Modules/MySQLContainer.php b/src/Modules/MySQLContainer.php
index b5daaea..00c6a90 100644
--- a/src/Modules/MySQLContainer.php
+++ b/src/Modules/MySQLContainer.php
@@ -5,7 +5,7 @@ declare(strict_types=1);
 namespace Testcontainers\Modules;
 
 use Testcontainers\Container\GenericContainer;
-use Testcontainers\Wait\WaitForLog;
+use Testcontainers\Wait\WaitForExec;
 
 class MySQLContainer extends GenericContainer
 {
@@ -14,7 +14,11 @@ class MySQLContainer extends GenericContainer
         parent::__construct('mysql:' . $version);
         $this->withExposedPorts(3306);
         $this->withEnvironment('MYSQL_ROOT_PASSWORD', $mysqlRootPassword);
-        $this->withWait(new WaitForLog('ready for connections'));
+        $this->withWait(new WaitForExec([
+            "mysqladmin",
+            "ping",
+            "-h", "127.0.0.1",
+        ]));
     }
 
     public function withMySQLUser(string $username, string $password): self
diff --git a/src/Utils/PortGenerator/RandomPortGenerator.php b/src/Utils/PortGenerator/RandomPortGenerator.php
index 8d3bbbc..1610a0a 100644
--- a/src/Utils/PortGenerator/RandomPortGenerator.php
+++ b/src/Utils/PortGenerator/RandomPortGenerator.php
@@ -27,4 +27,4 @@ class RandomPortGenerator implements PortGenerator
 
         return $port;
     }
-}
\ No newline at end of file
+}
diff --git a/src/Wait/BaseWaitStrategy.php b/src/Wait/BaseWaitStrategy.php
index 432aedf..80ff748 100644
--- a/src/Wait/BaseWaitStrategy.php
+++ b/src/Wait/BaseWaitStrategy.php
@@ -8,7 +8,6 @@ use Testcontainers\Container\StartedTestContainer;
 
 abstract class BaseWaitStrategy implements WaitStrategy
 {
-
     public function __construct(protected int $timeout = 10000, protected int $pollInterval = 500)
     {
     }
diff --git a/src/Wait/WaitForExec.php b/src/Wait/WaitForExec.php
index 044471c..ce7af35 100644
--- a/src/Wait/WaitForExec.php
+++ b/src/Wait/WaitForExec.php
@@ -5,7 +5,6 @@ declare(strict_types=1);
 namespace Testcontainers\Wait;
 
 use Closure;
-use Docker\API\Model\ContainersIdExecPostBody;
 use Docker\API\Model\ExecIdJsonGetResponse200;
 use Testcontainers\Container\StartedTestContainer;
 use Testcontainers\Exception\ContainerWaitingTimeoutException;
@@ -15,8 +14,6 @@ use Testcontainers\Exception\ContainerWaitingTimeoutException;
  */
 class WaitForExec extends BaseWaitStrategy
 {
-    protected ContainersIdExecPostBody $execConfig;
-
     /**
      * @param array<string> $command
      */
diff --git a/src/Wait/WaitForHealthCheck.php b/src/Wait/WaitForHealthCheck.php
index 74a13f2..9bef414 100644
--- a/src/Wait/WaitForHealthCheck.php
+++ b/src/Wait/WaitForHealthCheck.php
@@ -9,6 +9,7 @@ use Http\Client\Socket\Exception\TimeoutException;
 use Testcontainers\Container\StartedTestContainer;
 use Testcontainers\Exception\ContainerNotReadyException;
 
+//TODO: not ready yet
 class WaitForHealthCheck extends BaseWaitStrategy
 {
     public function __construct(protected int $timeout = 5000, protected int $pollInterval = 1000)
diff --git a/src/Wait/WaitForHttp.php b/src/Wait/WaitForHttp.php
index 906dc8b..87a840b 100644
--- a/src/Wait/WaitForHttp.php
+++ b/src/Wait/WaitForHttp.php
@@ -7,6 +7,7 @@ namespace Testcontainers\Wait;
 use Docker\Docker;
 use Testcontainers\Exception\ContainerNotReadyException;
 
+//TODO: not ready yet
 class WaitForHttp implements WaitStrategy
 {
     public const METHOD_GET = 'GET';
@@ -61,7 +62,7 @@ class WaitForHttp implements WaitStrategy
         $containerNetworks = $this->dockerClient->containerInspect($id)->getNetworkSettings()->getNetworks();
         $containerAddress = null;
         foreach ($containerNetworks as $network) {
-            if($network->getNetworkID() === $id) {
+            if ($network->getNetworkID() === $id) {
                 $containerAddress = $network->getIpAddress();
                 break;
             }
diff --git a/src/Wait/WaitForTcpPortOpen.php b/src/Wait/WaitForTcpPortOpen.php
index e6c3700..9545a88 100644
--- a/src/Wait/WaitForTcpPortOpen.php
+++ b/src/Wait/WaitForTcpPortOpen.php
@@ -9,6 +9,7 @@ use JsonException;
 use RuntimeException;
 use Testcontainers\Exception\ContainerNotReadyException;
 
+//TODO: not ready yet
 final class WaitForTcpPortOpen implements WaitStrategy
 {
     private Docker $dockerClient;
diff --git a/tests/Integration/OldTests/ContainerTest.php b/tests/Integration/OldTests/ContainerTest.php
index d7147b5..ed65412 100644
--- a/tests/Integration/OldTests/ContainerTest.php
+++ b/tests/Integration/OldTests/ContainerTest.php
@@ -18,6 +18,7 @@ use Testcontainers\Container\RedisContainer;
 class ContainerTest extends TestCase
 {
     //TODO: remove after check
+    //To make it work, fixed port should be first implemented
     protected function setUp(): void
     {
         $this->markTestIncomplete();
diff --git a/tests/Integration/OldTests/WaitStrategyTest.php b/tests/Integration/OldTests/WaitStrategyTest.php
index 060ca5b..9c164e9 100644
--- a/tests/Integration/OldTests/WaitStrategyTest.php
+++ b/tests/Integration/OldTests/WaitStrategyTest.php
@@ -54,104 +54,104 @@ class WaitStrategyTest extends TestCase
         $this->assertNotEmpty($version);
     }
 
-        public function testWaitForLog(): void
-        {
-            $container = Container::make('redis:6.2.5')
-                ->withWait(new WaitForLog('Ready to accept connections'));
+    public function testWaitForLog(): void
+    {
+        $container = Container::make('redis:6.2.5')
+            ->withWait(new WaitForLog('Ready to accept connections'));
 
-            $container->run();
+        $container->run();
 
-            $redis = new Client([
-                'scheme' => 'tcp',
-                'host'   => $container->getAddress(),
-                'port'   => 6379,
-            ]);
+        $redis = new Client([
+            'scheme' => 'tcp',
+            'host'   => $container->getAddress(),
+            'port'   => 6379,
+        ]);
 
-            $redis->set('foo', 'bar');
+        $redis->set('foo', 'bar');
 
-            $this->assertEquals('bar', $redis->get('foo'));
+        $this->assertEquals('bar', $redis->get('foo'));
 
-            $container->stop();
+        $container->stop();
 
-            $this->expectException(ConnectionException::class);
+        $this->expectException(ConnectionException::class);
 
-            $redis->get('foo');
+        $redis->get('foo');
 
-            $container->remove();
+        $container->remove();
+    }
+
+    public function testWaitForHTTP(): void
+    {
+        $container = Container::make('nginx:alpine')
+            ->withWait(WaitForHttp::make(80));
+
+        $container->run();
+
+        $ch = curl_init();
+        curl_setopt($ch, CURLOPT_URL, sprintf('http://%s:%d', $container->getAddress(), 80));
+        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
+
+        $response = (string) curl_exec($ch);
+
+        curl_close($ch);
+
+        $this->assertNotEmpty($response);
+    }
+
+    /**
+     * @dataProvider provideWaitForTcpPortOpen
+     */
+    public function testWaitForTcpPortOpen(bool $wait): void
+    {
+        $container = Container::make('nginx:alpine');
+
+        if ($wait) {
+            $container->withWait(WaitForTcpPortOpen::make(80));
         }
 
-        public function testWaitForHTTP(): void
-        {
-            $container = Container::make('nginx:alpine')
-                ->withWait(WaitForHttp::make(80));
+        $container->run();
 
-            $container->run();
-
-            $ch = curl_init();
-            curl_setopt($ch, CURLOPT_URL, sprintf('http://%s:%d', $container->getAddress(), 80));
-            curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
-
-            $response = (string) curl_exec($ch);
-
-            curl_close($ch);
-
-            $this->assertNotEmpty($response);
+        if ($wait) {
+            static::assertIsResource(fsockopen($container->getAddress(), 80), 'Failed to connect to container');
+            return;
         }
 
-        /**
-         * @dataProvider provideWaitForTcpPortOpen
-         */
-        public function testWaitForTcpPortOpen(bool $wait): void
-        {
-            $container = Container::make('nginx:alpine');
+        $containerId = $container->getId();
 
-            if ($wait) {
-                $container->withWait(WaitForTcpPortOpen::make(80));
-            }
+        $this->expectExceptionObject(new ContainerNotReadyException($containerId));
 
-            $container->run();
+        (new WaitForTcpPortOpen(8080))->wait($containerId);
+    }
 
-            if ($wait) {
-                static::assertIsResource(fsockopen($container->getAddress(), 80), 'Failed to connect to container');
-                return;
-            }
+    /**
+     * @return array<string, array<bool>>
+     */
+    public function provideWaitForTcpPortOpen(): array
+    {
+        return [
+            'Can connect to container' => [true],
+            'Cannot connect to container' => [false],
+        ];
+    }
 
-            $containerId = $container->getId();
+    public function testWaitForHealthCheck(): void
+    {
+        $container = Container::make('nginx')
+            ->withHealthCheckCommand('curl --fail http://localhost')
+            ->withWait(new WaitForHealthCheck());
 
-            $this->expectExceptionObject(new ContainerNotReadyException($containerId));
+        $container->run();
 
-            (new WaitForTcpPortOpen(8080))->wait($containerId);
-        }
+        $ch = curl_init();
 
-        /**
-         * @return array<string, array<bool>>
-         */
-        public function provideWaitForTcpPortOpen(): array
-        {
-            return [
-                'Can connect to container' => [true],
-                'Cannot connect to container' => [false],
-            ];
-        }
+        curl_setopt($ch, CURLOPT_URL, sprintf('http://%s:%d', $container->getAddress(), 80));
+        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
 
-        public function testWaitForHealthCheck(): void
-        {
-            $container = Container::make('nginx')
-                ->withHealthCheckCommand('curl --fail http://localhost')
-                ->withWait(new WaitForHealthCheck());
+        $response = curl_exec($ch);
 
-            $container->run();
+        $this->assertNotEmpty($response);
+        $this->assertIsString($response);
 
-            $ch = curl_init();
-
-            curl_setopt($ch, CURLOPT_URL, sprintf('http://%s:%d', $container->getAddress(), 80));
-            curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
-
-            $response = curl_exec($ch);
-
-            $this->assertNotEmpty($response);
-            $this->assertIsString($response);
-
-            $this->assertStringContainsString('Welcome to nginx!', $response);
-        }
+        $this->assertStringContainsString('Welcome to nginx!', $response);
+    }
 }